"New" old K75 in the stable

[DrPaul]

I have just acquired a 1987 K75. I belive it is an "S" model with smallish windscreen and sport fairing. It is a deep red color. It was literally parked in a barn 17 years ago. There are 8K miles on the odometer and aside from being dirty it appears to be "all there" with no visible damage. The PO said it was running fine when he put it up in 1990! However, the fuel system was not drained when the bike was laid up and I anticipate there will be issues there.

I'm an "R" guy and have no experience with these machines but I understand they were considered to be a very reliable powerplant and drivetrain. I did not receive any manuals with the bike and am in need of some advice from my BMWMOA brethren. To wit:

1) A recommendation for a good service manual.
2) What fluids (crankcase oil, tranny, FD) should I use.
3) What fuel octane rating is recommended.
4) It will need tires! I suspect those on it now are the originals. Suggestions?
5) The key I have seems to work the seat/helmet lock but not the ignition switch. Were there two keys for this bike?
6) What spark plugs are suggested?
7) Egads! It's liquid cooled!! Would any 50/50 mix for aluminum engines suffice?

I know I'll have more questions. Thanks in advance for your help!!

Dr. Paul

[GregFeeler]

I have just acquired a 1987 K75. I belive it is an "S" model with smallish windscreen and sport fairing. It is a deep red color. It was literally parked in a barn 17 years ago. There are 8K miles on the odometer and aside from being dirty it appears to be "all there" with no visible damage. The PO said it was running fine when he put it up in 1990! However, the fuel system was not drained when the bike was laid up and I anticipate there will be issues there.

First, congratulations on such a find. Once you get the storage issues delt with, you should have a very fine bike.

There are two models of K75 with a factory fairing - the "S" (with a disk rear brake) and the "C" (with a drum rear brake). Both are fine bikes, but the rear tire size is different between the two.


I'm an "R" guy and have no experience with these machines but I understand they were considered to be a very reliable powerplant and drivetrain. I did not receive any manuals with the bike and am in need of some advice from my BMWMOA brethren. To wit:

1) A recommendation for a good service manual.

Clymer seems to be the most comprehensive. Just remember that all after market service manuals have some errors, so if something seems like whacky advice, no harm in checking it on some of the lists.

http://www.clymer.com/Book.aspx?bid=485&title=BMW+K-Series%2c+1985-1997


2) What fluids (crankcase oil, tranny, FD) should I use.

Transmission & grearbox: 80w90, or 90 Hypoid GL5 gear lube
Engine: 15w50

Personally, I go for the synthetic lubricants. However, in your case I'd change the fluids, run the bike for several hundred miles, and change again. Maybe the "good stuff" the second time.

Also, get the BMW oil filter and the special wrench you'll need to change it. You can get those at your local dealer or from the big on-line dealers (Bob's, A&S, Max, etc.)

For fork oil you'll need to know if your bike is an S or a C. They use different specifications.


3) What fuel octane rating is recommended.

I'd start with premium. These are high compression engines, and many people have advanced the timing to get a bit more performance. If that's been done to your bike, you'll need premium for sure.


4) It will need tires! I suspect those on it now are the originals. Suggestions?

My suggestions will depend on if your bike is an S or a C since they have different sized rear wheels. There are some tire models which are available for the S but not the C. Also, it would be a big help to to know about your riding style and the kind of roads in your area.

5) The key I have seems to work the seat/helmet lock but not the ignition switch. Were there two keys for this bike?

Not out of the box. You'll need to get something changed to match something.



6) What spark plugs are suggested?
Bosch X5DC


7) Egads! It's liquid cooled!! Would any 50/50 mix for aluminum engines suffice?

No, you need to get a coolant that is silicate & phosphate free. Many of the newer formulations meet this requirement, but check the bottle. Also, BMW recommends a 60/40 ratio (water/coolant).


I know I'll have more questions. Thanks in advance for your help!!

A couple of other things I'll offer:

Remove and flush the tank, then run several tanks of gas with a rich mixture of Chevon Techron (1oz/gal or more). That stuff is amazing and will do a wonderful job of cleaning the fuel system and injectors.

Get TWO new fuel filters. Replace the one in the tank and keep a new one in the tail piece "trunk" behind/under the seat. The K-bike fuel filters are designed to remove ALL the water in the fuel and can plug with just one or two bad tanks of gas.

Check the crank case vent hose on the back left side of the engine. It's about 8 inches in on the back left corner of the engine. Run your hand over it for cracks. They can crack and leak air which screws up overall engine running. Cheap and relatively easy to replace.

Pull the rear drive off the swing arm and check the drive shaft splines for grease. Unlike your airhead (assuming it's not a paralever) the K-bike drive shafts don't run gear oil - the coupling splines are lubed with grease like the clutch splines on all BMW bikes. Do this about every 10~14,000 miles. By leaving the rear drive hanging off the rear shock and tying it back, you can do this job in less than an hour.

Speaking of splines, like all BMW bikes, the K75 needs it's clutch splines greased from time to time. If you have stiff/sticky shifting, especially from 3rd to 2nd, then you are likely due.

Get the Clymer manual and read it over, but ask all the questions here you want. Hope this helps.

[98lee]

Do NOT attempt to start the bike!!

If the bike was put away without draining the fuel and the fuel level was above the fuel pump vibration damper, the old fuel will have turned the rubber vibration damper to gooo. If you are lucky, and no one has attempted to start the bike, the gooo will be just in the fuel tank (easy and cheap to remedy). If you attempt or someone already has attempted to start the bike, the fuel pump (if it still works) will pump the gooo through the system thereby contaminating the fuel pump and the very fine screens and orfices inside the injectors.

Best plan is to remove and drain the tank.

Remove fuel pump, vibration damper,and filter from the tank.

Inspect inside of tank. It should be clean shiney BARE aluminum (no evidence of any coating) no film of any kind. If so, you might be in luck. If not clean , clean , clean.

Inspect vibration damper. It should be hard with no signs of being desolved by the stale gas. Should have a very distinct groove where it mates with the upper of the two of the bumps around the circumferance of the pump.

BENCH TEST the pump. This way you do not run the risk of further contaminating the system. Small post +. Large post -. If it whrrrs, that's a good thing. If it's quiet or if it hums without rotating, that's a bad thing. Worst case, replace (about $220) best case, bench clean.

Install NEW fuel filter, new or cleaned and working fuel pump, good condition vibration damper, new internal hoses (F.I. and immersion rated).

Now if you try to start it, you will do no further harm to the injectors and it might start.

Make sure you have a VERY good or New battery when you try to start it for the first time. Low battery levels will cause the starter relay contacts to weld together.

Good luck. You will enjoy the bike.


:dance :dance :dance

[Bob_M]

It is safe to assume the piston rings are bone dry. When you change the plugs you may want to squirt a bit of Marvel Mystery Oil into the cylinders and roll the bike back and forth with the transmission in gear, to wet the cylinders and rings. The oil will burn out clean when the bike fires up.

Congrats! The mythical "barn find" lives. :bow

[98lee]

Congrats! The mythical "barn find" lives. :bow

Keep us informed!!:lurk


:dance :dance :dance

[tessler]

Congrats on the new ride and listen to what Greg and Lee had to say!

Pics, man, pics!

[DrPaul]

Many thanks to Greg, Lee and Bob. Your information is greatly appreciated. Greg, my K75 has the disk rear brake so I guess it is the "S" model. I will order a Clymer for it. Your oil and gear lube recommendations are exactly what I run in my R1150RT. I have a BMW oil filter wrench for my R; I see the K75 has the enclosed filter cavity like my buddy's K1200LT. I think the filter diameters are the same. I've used Beemer Boneyard for many service parts (my local dealer closed this past year) with good results. My R is an oilhead so I'm familiar with the dry shaft. I will lube the splines as you suggest. I presume a suitable moly spline paste is preferred. I'm tempted to go ahead and do the clutch splines while it is apart. Is that a major PITA? Lee, thanks for the suggestions on the fuel system. Do you have a recommendation on a battery? I have the Exide AGM in my R. Is the alternator belt driven and, if so, should I replace the belt on a 20 year old bike w/ 8K miles? Bob, thanks for the Marvel Mystery oil tip. That stuff is great!

I'll keep everyone posted on my progress! Thanks again.

[bikerfish1100]

oil filter and fuel filter is same item your R bike uses. Beemerboneyard seems to have a "best price" on Bosch oil filters. The K&N 163 filters are also well rated, and attractively priced http://cyclegear.com/spgm.cfm?L1=&L2=&L3=&L4=&item=TUC_40-1450_G&tier2=142

[98lee]

An S in Marakesh Red?? With only 8000 miles? What a GREAT find!!:clap


Of course I am a little prejudice, Here are two of my three Marakesh Red K75Ss:
10753

Let me know the last five numbers on the VIN# and I can tell you if it was made before mine. Mine was built in the first week of US K75S production and is the 81st K75S built for the US.

BEST battery: OdesseyPC680 or PC680MJ GREAT battery!!

While the tank is off: the radiator filler is under the tank. Flush and fill with fresh coolant. IMPORTANT: the overflow hose from the radiator to the overflow bottle MUST NOT have ANY cracks. If it does it will allow coolant out of the sytem and suck air into the system.

Check to see if the fan can be turned freely.

Honda Moly 60 paste seems to be the lube of consensus.

:lurk :lurk :lurk

:dance :dance :dance

[GregFeeler]

Many thanks to Greg, Lee and Bob. Your information is greatly appreciated. Greg, my K75 has the disk rear brake so I guess it is the "S" model. I will order a Clymer for it. Your oil and gear lube recommendations are exactly what I run in my R1150RT. I have a BMW oil filter wrench for my R; I see the K75 has the enclosed filter cavity like my buddy's K1200LT. I think the filter diameters are the same.

They should be.

I've used Beemer Boneyard for many service parts (my local dealer closed this past year) with good results. My R is an oilhead so I'm familiar with the dry shaft. I will lube the splines as you suggest. I presume a suitable moly spline paste is preferred.

Yes. My favorite is the Honda Moly 60. I just checked the rear drive shaft splines on one of my K75s after 10,000 miles and it still had good lubrication.


I'm tempted to go ahead and do the clutch splines while it is apart. Is that a major PITA?

Depends on your definition of PITA. I would say it is for many folks. Basically, you have to unbolt the rear of the frame from the transmission and rotate it up on the front bolts so you can pull the tranny out the back. You'll have to support the engine from below (scissor jack, etc.), use a cherry picker or make a harness to pull up and support the frame. Nothing here is really difficult, but a good bit of work.

Personally, I'd do this in a couple of stages. First, I'd get the bike cleaned up inside and out (I especially like Lee's fuel system clean/test process), get some good tires, etc. and ride it. You may find the fork head bearing grease has turned to mud - things like that. This assumes the transmission shifting is ok.

Then I'd pull the tranny and do the spline lube, and you'll have it all good for the road. Even with "dry" splines, the relatively small miles you'll put on road testing shouldn't be an issue.

OTOH - you might just want to go through it front to back all at once as a big project, which is just fine as well.


Lee, thanks for the suggestions on the fuel system. Do you have a recommendation on a battery? I have the Exide AGM in my R. Is the alternator belt driven and, if so, should I replace the belt on a 20 year old bike w/ 8K miles? Bob, thanks for the Marvel Mystery oil tip. That stuff is great!

I'll keep everyone posted on my progress! Thanks again.

Do that - and do post some pictures!

[GregFeeler]

An S in Marakesh Red?? With only 8000 miles? What a GREAT find!!:clap


Of course I am a little prejudice, Here are two of my three Marakesh Red K75Ss:
10753



Oh - VERY nice brace of K75S's!! :clap :clap

[PGlaves]

Greg,

You are mixing K and R metaphors (or is it semaphors) here. There is no need to move the rear subframe on a K. But, the centerstand is located on the transmission so you have to secure the front wheel very well and block/jack under the sump to support the bike.

But you knew this - you just got your Oilhead and K bike mixed up!

[GregFeeler]

Greg,

You are mixing K and R metaphors (or is it semaphors) here. There is no need to move the rear subframe on a K. But, the centerstand is located on the transmission so you have to secure the front wheel very well and block/jack under the sump to support the bike.

But you knew this - you just got your Oilhead and K bike mixed up!

Doh!!! Either too much - or not enough - coffee today!!! :coffee :coffee

[DrPaul]

Good evening! And again, thanks to all who have contributed. The two main discoveries today are a shot fuel pump and radiator fan. The fan blade was twisted off the motor shaft and the motor is frozen. I'll bet the motor/blade assembly is not available alone and I will have to buy the shroud as well. Oh, well.

Had to drain the cooling system and remove the radiator to get the fan unit out. The coolant was pretty clean and the system was full so I'm optimistic nothing had frozen. Because the bike had sat with fuel in it for 17 years, I pulled the air box, fuel rail and throttle bodies. I would like to pull the injectors for a good cleaning but I can't figure how to get them out of the head. Advice here would be greatly appreciated. Pulled the plugs and they looked almost new. Filled the cylinders with MMO and will let sit for the night. More later .....

Paul

[DrPaul]

Let me know the last five numbers on the VIN# and I can tell you if it was made before mine. Mine was built in the first week of US K75S production and is the 81st K75S built for the US.

Lee,
Those are some beautiful bikes! The last 5 numbers of my VIN are: 50141

Paul

[cafecubano]

Let me know the last five numbers on the VIN#

Lee, If you don't mind I want in on this. Here are my last five vin#s 50067
Armando

[Beemer01]

The only additional contribution I can make is that there are some amaziing internet resources available to augment your Clymer manual -

http://www.ibmwr.org/ktech.shtml

http://bmw.k100rs.free.fr/files/repair_manuals/BMW%20K1100LT%20K1100RS%20-%20ENG.pdf

Much of what is here will be relevant for your K75. :bikes

[colemanrobh]

What a generous, informed, and supportive series of responses to DrPaul's questions! I learned much, as I always do when the experienced share their knowledge in this forum. You guys rock, I must say. :clap

[98lee]

Lee,
Those are some beautiful bikes! The last 5 numbers of my VIN are: 50141

Paul

I WANT YOUR BIKE!!!:heart

Our bikes are sisters from the same litter!
Mine is # 81
Yours is # 141

They were both built in the first month of US spec K75S production May of 1986.
But since they were introduced mid year they called them '87 models.

They built 325 for the US market that month.

Not suprised about the fan. New fan motors are available for $65 and fuel pumps for $200 from a guy who sells all the Bosch stuff for old Kbikes. I'll try to get you his number tomorrow. I might have a good vibration damper for you.

Don't take too many things apart yet. Is the inside of the fuel rail clean or does it have a coating of brownish gooo in it?

If it is clean, put the injection system back together and try to start the bike. If the injectors are partially fouled, running some Techroline in a few tanks might clean them up.

If the injectors are really fouled, it's not worth messing with them. I can tell you where to get rebuilt and flow checked ones for $12ea. no exchange.

If you really must know how to pull the injectors, but don't do it unless:

A. The fuel rail is full of the brown goo
and
B. you have the new injectors ready to put in


Step1
Thoroughly clean aroun the base of the injectors and the head with brake clean and a small brush and finish of with compressed air to remove all traces of sand, grit and dirt that could fall into the cylinder when you pull the injectors.

Step 2
Reattach the fuel rail to the injectors. Do not bolt rail to head.

Step 3
Gently rock the fuel rail (and injectors) to loosen them from the head.
They are only held in by the O-ring that also seals them to the head.

P.S. The rebuilt injectors come with all new O-rings top and bottom.


:dance :dance :dance

[98lee]

Lee, If you don't mind I want in on this. Here are my last five vin#s 50067
Armando

Holy Sh*t! It's a family reunion!!!!:clap :clap :clap

Your bike was also built in the first week of production of US spec K75Ss. In fact your bike and my bike were probably built on the SAME DAY. Yours is the 67th ever built and mine is the 81st.

Your next move should be to join BMW NORCAL. I am going to be cohosting a tech session for them in January.

For 2 valve Kbikes I'm going to be offering valve adjustments, throttlebody sync, rear spline lube, tire balance, tire plugging practice and help with any other issues someone might want to look at.

I'm going to Private Message you my phone number since I just live across the bay.
I'll hook you up (since were family and all)

Also I noticed in a previous post that you mentioned about not being happy with the bar placement. I have several options you might want to try.



:dance :dance :dance

[DrPaul]

What a generous, informed, and supportive series of responses to DrPaul's questions! I learned much, as I always do when the experienced share their knowledge in this forum. You guys rock, I must say. :clap
I'll second that!
Paul

[DrPaul]

Don't take too many things apart yet. Is the inside of the fuel rail clean or does it have a coating of brownish gooo in it?

If it is clean, put the injection system back together and try to start the bike. If the injectors are partially fouled, running some Techroline in a few tanks might clean them up.

If the injectors are really fouled, it's not worth messing with them. I can tell you where to get rebuilt and flow checked ones for $12ea. no exchange.
Lee,
Thanks for the advice on the injectors. When I removed the fuel return line, the gas in the rail was murky brown but no sludge. The rail was difficult to remove from the injectors due to deposits on the O-rings but it finally relented. The injector inlets look fine other than having some brownish deposit on them which easily wipes off. I think I'll clean the fuel lines and rail really well and reinstall. Is there was a way to test/clean the injectors without removal? If I could just squirt some WD-40 through those puppies ...

I bit the bullet on the fuel pump, vibration damper and fan unit and ordered new from Beemer Boneyard yesterday. Next will be tires. What tires do you run on yours?

Paul

[PGlaves]

I got the baby of the litter - #50019.

[bikerfish1100]

Lee,
Next will be tires. What tires do you run on yours?

Paul

OH NO, HERE WE GO AGAIN!!

[breyfogle]

.... I would like to pull the injectors for a good cleaning but I can't figure how to get them out of the head. Advice here would be greatly appreciated.

There is nothing holding the injectors into the head except O-ring friction. If you have the fuel rail off, just pull ....

[deilenberger]

There is nothing holding the injectors into the head except O-ring friction. If you have the fuel rail off, just pull ....Yup.. although the O rings can stick in there pretty good. A bit of WD40 sprayed around the bottom of the injector where it goes into the head will sometimes help loosen it up.

Before even trying to start it - take the removed injectors to an injector service center (look under diesel truck service in the YellowPages..) and have them cleaned. They will reverse flush them - which is important to get the goop out of the input screens. If you try to start it without doing this you're likely to force the goop through the screens and plug the injectors - making them unusable.

Plan on spending $10-25 each to have this done. They should come back to you with the new O rings installed.

Also - take the fuel filler off the tank - and take a good look at the inside of the tank. Sitting that long can result in moisture condensing into the fuel and water ending up at the bottom of the tank. I'd suggest removing the fuel pump and (1) see if it runs - hooked to an external battery (2) inspect the rubber ring it mounts in - these turn to a terrible black mush when left in old gasoline. Chances are fairly good that the pump has rusted up and will not turn. No real fix for this short of a new pump. Try not to blow yourself up doing this..

Inspect the hoses in the tank for splitting, and plan on replacing the fuel filter.

These are before even trying to start it checks..

[98lee]

Is there was a way to test/clean the injectors without removal?

Start it. Drive it. Put some Techroline or other good injector cleaner in the tank and ride. If it runs well, all is good. If it runs so so, it might clear up. If it runs like crap, try the rebuilt injectors.

Hint: if you can get it running and if you have a friendly auto mechanic, have him put it on his exhaust analyzer. Also check the difference in exhaust pipe temperature on each primary right as it leaves the head. You can use one of those point and shoot infrared temp sensor guns (at the moment , the proper name escapes me:gerg) Harbor Freight $39


Next will be tires. What tires do you run on yours?

Metzler Lasertecs Good handling, good traction. But not a high milage tire.
I get about 4-5000 miles out of them, but my riding is about 70% semi-aggressive fun riding on the twisties. A higher milage, more touring orientated tire, would lower cost but at the expence of a little bit of the fun factor.:rocker


:dance :dance :dance

[98lee]

I got the baby of the litter - #50019.

Baby? She'd probably be the matriarch of the whole family, if she's still alive!:bow :bow :bow :bow

Do you still have her?

Yours or Voni's?

Color? (Excuse the redundant question if it's Voni's)



How many more of the original litter are still kicking? Anyone??

All US spec K75Ss were frame (VIN) numbered consecutively, starting with the last six #s of 150001.

The original litter from May of 1986 was 150001 thru 150325.

The last of the line was 154600 that was born on September 1994.


:dance :dance :dance

[GregFeeler]

My personal favorite for the K75S right now are the Dunlop D205 radial tires. AFAIK, these are the only radials available to fit the narrow rims of the klassic K-bikes. When I put a set on my '92 K75S they transformed it. MUCH quicker, but very stable handling. Combined with a new, good, rear shock and some fork service including 10w BMW oil, it's a kick to ride. Don't know about tire life or rain performance, but I've never had bad rain performance from any radial - so far.

Others I've used: Michelin Mac50's. Very nice, neutral tire with good life (8,000+) and good trustworthy handling. Metzeler ME33/55 (the original ones). Very sticky, but melted like butter. 5,000 miles was the max from the back I ever got - if that. There are new Lasertecs from Metzeler with the same tread pattern but new carcass design. Don't know about them. The Metzeler ME880's can be fitted, and are a great long-distance touring tire, but IMHO would be the wrong tire for a K75S if you want to get and of the "S" out of it.

[DrPaul]

Also - take the fuel filler off the tank - and take a good look at the inside of the tank. Sitting that long can result in moisture condensing into the fuel and water ending up at the bottom of the tank. I'd suggest removing the fuel pump and (1) see if it runs - hooked to an external battery (2) inspect the rubber ring it mounts in - these turn to a terrible black mush when left in old gasoline. Chances are fairly good that the pump has rusted up and will not turn. No real fix for this short of a new pump. Try not to blow yourself up doing this..

Inspect the hoses in the tank for splitting, and plan on replacing the fuel filter.

These are before even trying to start it checks..
Thanks for the advice on the injectors. I'll do that. As far as the fuel pump and filter, the pump was shot and a new one is on order. The tank has cleaned up pretty well and the hoses seem good. The damper was soft goo but intact and I have ordered a replacement as well. New filters all round.

Paul

[deilenberger]

Is there was a way to test/clean the injectors without removal?

Start it. Drive it. Put some Techroline or other good injector cleaner in the tank and ride. If it runs well, all is good. If it runs so so, it might clear up. If it runs like crap, try the rebuilt injectors.
Perhaps I don't have a lot of experience - just helped getting about 5-6 old K bikes running that had been left with fuel in the tank, but this sounds like a recipe for trouble.

As I noted above - and this was on every one of these bikes - there was sludge in the fuel rail. It did sludge up the injectors, and in 4 cases - the fuel pump wasn't gonna pump anyway - the rollers in them like to rust solid when left in water at the bottom of a fuel tank. In several cases - with the newer gas formulations - the rubber mount for the pump turned into tar, and if the fuel pump did run, the tar was sucked into it and turned the pumps into trash.

The OP mentioned he found brown colored stuff in the fuel rail. That's rust from inside the steel rail caused by water sitting in the fuel rail for an extended period of time. The rust is also now in the input screens of the injectors. The injectors might be saved.. but if you try to pump fuel through them with the rust in the screens they are junk.

As far as "rebuilt injectors" - there is no way to disassemble and reassemble injectors to replace parts. The input screens can be removed and replaced, and the O rings can be R&R - but that's about it. "Rebuilt" injectors are typically ones that were removed from a running bike and perhaps cleaned (sometimes not..) If you look at how they're built you can see why they can't be disassembled without destroying them.

[deilenberger]

Thanks for the advice on the injectors. I'll do that. As far as the fuel pump and filter, the pump was shot and a new one is on order. The tank has cleaned up pretty well and the hoses seem good. The damper was soft goo but intact and I have ordered a replacement as well. New filters all round.

PaulPaul - sounds good. I'm hopeful the injectors will clean up OK. And do make sure to really flush out the fuel rail (some people have gone as far as putting small ball bearings in it and shaking it like mad) to get the remaining rust out of it (why BMW put steel in the system.. and apparently poorly plated steel..)

Good luck!

[DrPaul]

Paul - sounds good. I'm hopeful the injectors will clean up OK. And do make sure to really flush out the fuel rail (some people have gone as far as putting small ball bearings in it and shaking it like mad) to get the remaining rust out of it (why BMW put steel in the system.. and apparently poorly plated steel..)

Good luck!I was able to remove the injectors without damage to them or me. I soaked them overnight along with the rail in WD-40 and flushed them out as good as I could. The rail looks pretty good inside. When I get the fuel pump and filter in I'll get her back together and see what I've got. If it starts and runs, great. If not I'll be looking for three injector valves. Any leads on those parts would be greatly appreciated. Thanks.

Paul

[From MARS]

Sorry for the hijack, but I was told by a hose and o-ring manufacturer back when I was working on yachts, to not use WD40 on anything rubber. It softened the rubber and led to failure. Anybody else heard this?

Tom

[CustomSarge]

Once clean, hook everything back up Except putting the injectors & rail into the head.

> Get a couple pieces of cardboard to lay the injectors/rail on & separate them from the engine.
> Turn on ignition & Just Tap the starter, check that the pump spins up.
> Given pump's ok, hit the starter for ~2 sec. Look for a ~50 degree cone pattern of misted gas from each injector.

>>--------{THIS IS REAL DANGEROUS, Done Stupidly}---------<<

> Given good patterns, put the cardboard Way away & assemble injectors/rail to engine.
> Engine should start, but beware of fouling plugs with the oil(s) in the head & intake manifold. Having a couple clean sets around can save time.

> If patterns bad, clean as per previous posts.
> If no pattern: stuck pintle/bad injector. You can *try* taking a large (#3) phillips screwdriver and *barely* push on the pintle. This can break free a varnish stuck pintle. While Many disagree on doing this, I've successfully done it on a K75 where all 3 were stuck.

Just an addition, all previous posts are good approaches; except I far prefer to clean/verify Then try to start.
Congratulations on striking red gold & Good Hunting... <<<)))

[DrPaul]

Sorry for the hijack, but I was told by a hose and o-ring manufacturer back when I was working on yachts, to not use WD40 on anything rubber. It softened the rubber and led to failure. Anybody else heard this?

TomTom, I removed the O-rings from both ends of the injectors before soaking and coated them with silicon grease. I don't know if WD-40 damages the rubber but it certainly seems to make it swell.

Paul

[DrPaul]

I've removed, cleaned and inspected the throttle bodies and lightly oiled the butterfly shaft and other moving parts. The TBs are back in and throttle and fast idle cables attached. Everything works smoothly. The air box with the wierd HUGE valve body mounted in the top is back on. I'm waiting for fuel pump, fuel, air and oil filters, plugs and radiator fan assembly. The tank is pretty clean and all hoses are good by inspection. Once everything is back on I believe I'll do an injector test as describes by CustomSarge VERY CAREFULLY outdoors. If they spray, the injectors/fuel rail assembly goes back on for a test start. If it runs, great. I'll change all fluids (at least 17 years old), flush and bleed brakes (thank goodness there is no ABS) and check pads. They are probably OK with only 8K miles and I don't imagine age hurts them. While waiting for tires to arrive, I'll remove the rear wheel, pull the pumpkin and lube the drive shaft. With new tires on it will be test ride time! Now, for a couple of questions:

1) The tires on the bike now are Michelins (130/90 V-17 rear and 100/90 V-18 front). Many tire makers I've searched do not show these exact sizes and most are bias ply tires. Does anyone have a specific radial tire recommendation?

2) The key I have seems to be a "valet" key. It works the seat/helmet lock but will only turn on the park lamp but not the ignition. I've got the switch apart and am able to turn the shaft to each of the 3 positions but the key just won't go to the "run" position. Can I order a replacement from BMW?

3) OK, more than a couple of questions. What brand/weight fork oil is best?

Paul

[GregFeeler]

I've removed, cleaned and inspected the throttle bodies and lightly oiled the butterfly shaft and other moving parts. The TBs are back in and throttle and fast idle cables attached. Everything works smoothly. The air box with the wierd HUGE valve body mounted in the top is back on. I'm waiting for fuel pump, fuel, air and oil filters, plugs and radiator fan assembly. The tank is pretty clean and all hoses are good by inspection. Once everything is back on I believe I'll do an injector test as describes by CustomSarge VERY CAREFULLY outdoors. If they spray, the injectors/fuel rail assembly goes back on for a test start. If it runs, great. I'll change all fluids (at least 17 years old), flush and bleed brakes (thank goodness there is no ABS) and check pads. They are probably OK with only 8K miles and I don't imagine age hurts them. While waiting for tires to arrive, I'll remove the rear wheel, pull the pumpkin and lube the drive shaft. With new tires on it will be test ride time! Now, for a couple of questions:

Does my heart good to see someone take the time to do it right. :thumb

1) The tires on the bike now are Michelins (130/90 V-17 rear and 100/90 V-18 front). Many tire makers I've searched do not show these exact sizes and most are bias ply tires. Does anyone have a specific radial tire recommendation?

My pick: Dunlop D205's: 110/80ZR18 front, and 140/80ZR17 rear. I believe these are the *only* radial tires available for those rims. I like mine a lot.

2) The key I have seems to be a "valet" key. It works the seat/helmet lock but will only turn on the park lamp but not the ignition. I've got the switch apart and am able to turn the shaft to each of the 3 positions but the key just won't go to the "run" position. Can I order a replacement from BMW?

Don't know on this one. I'd call Bob's BMW and ask. Also, if you have a competent locksmith in your area who works with European cars, he/she might be able to cut you a key.

3) OK, more than a couple of questions. What brand/weight fork oil is best?

Paul

Several good brands: BMW, BelRay, Spectro, etc. "7.5" is the BMW spec so try that if you like. I have 10w BMW oil in my K75S and although it's a bit firm, I like it. However, stay within brands as you try different weights. The common wisdom is that there is often more difference between two brand's 10w than there is between the same brand's 7.5 and 10w. Also, the early K75S's had "sport" forks and used a different amount of oil in each side. The spec escapes me now, but that new Clymer manual should have it. :groovy

[DrPaul]

Thanks so much for the advice. I'll go with the Dunlops as I prefer a radial tire. I mail ordered the Clymer manual but it hasn't arrived yet. When it does, hopefully I can stop asking so many questions!

Paul

[lostandwandering]

Congratulations Paul. I made a similar "find" a year ago, a K75S with 8700 miles on it (vin .....50905) unfortunately mine was the blue/green color.
Have you had a chance to look at the brakes yet? If the fuel system had brown sludge in it you'll probably find the same thing in the brake lines and Mcylinders.

Good luck with your "new" bike. After its initial clean up mine has been a real joy to ride this past summer.

[98lee]

50905 born March 1987:wave


:dance :dance :dance

[DrPaul]

Congratulations Paul. I made a similar "find" a year ago, a K75S with 8700 miles on it (vin .....50905) unfortunately mine was the blue/green color.
Have you had a chance to look at the brakes yet? If the fuel system had brown sludge in it you'll probably find the same thing in the brake lines and Mcylinders.

Good luck with your "new" bike. After its initial clean up mine has been a real joy to ride this past summer.Not really carefully evaluated the brakes yet. The fluid is dark in both systems. The front brake works but the rear does not seem to grab at all. I plan to tackle the brakes this weekend. I imagine I may need to remove the rear caliper and force the pucks back into their bore then flush. I'm pretty experienced with brakes and have done the control and wheel circuits on my R1150RT several times. This K75 system is sooooo much simpler. Thanks for the reminder!
Paul

[GregFeeler]

So...where are the pictures?? :dance

[DrPaul]

So...where are the pictures?? :danceGreg,
I tried to upload one photo last night but I received an error message that the file was too large (way too large). There is 156.3 Kb file size limit per upload. Any way around that other than to take the photos at a lower resolution?

Paul

[jstanco]

my brick is a 93 k75 and i worship it....it has 7007 miles on it right this minute while it sits in my cold oklahoma garage. Unseasonably cold tonight 35 at best and windy...

She is warm and toasty with the her two friends...

[DrPaul]

The rear brake MC is sludged up and piston is frozen. Will probably have to replace or rebuild. Anyone have a lead on a rebuilt MC? Beemer boneyard wants $50 just for the rebuild kit. The caliper looks good. Both pucks move freely and pads are barely worn. Also, the rear reservoir looks to be in poor condition and will likely need replacement.

Paul

[98lee]

34311451863 fluid reservoir, square corners - Up to 09/1987 $19.00 list

$15.20 Chicago BMW if you want to wait a while (goes in with regular stocking orders)

$17.10 Chicago BMW if you tell them VOR (vehicle on repair) they will order it that day



M/C: http://cgi.ebay.com/ebaymotors/BMW-Rear-Brake-Master-Cylinder-K75-K100_W0QQitemZ220174501539QQihZ012QQcategoryZ35604 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem (for DrPaul's eyes only):hide


:dance :dance :dance

[DrPaul]

I've put a bid on the MC and will get a reservoir ordered. Thanks SO MUCH for your help. This forum is priceless!

Paul

[DrPaul]

Good morning K-bike wizards,
I'm still waiting for my mail-ordered Clymers to arrive. ITMT, I've discovered the fork turns VERY stiffly and is in need of bearing removal, cleaning and repacking. I would like to get this done while the wheels are off waiting for tires. I have the bike on a lift with the front fairing/headlamp/instrument cluster and front wheel off. The calipers are also off the fork legs. It seems that the front brake hydraulic tube that runs through the steering head may need to be removed. If so, how does it come out? If it can stay in, what is the next step in getting to the bearings? What grease is recommended?

As always, thanks for any information.

Dr. Paul

[GregFeeler]

Good morning K-bike wizards,
I'm still waiting for my mail-ordered Clymers to arrive. ITMT, I've discovered the fork turns VERY stiffly and is in need of bearing removal, cleaning and repacking. I would like to get this done while the wheels are off waiting for tires. I have the bike on a lift with the front fairing/headlamp/instrument cluster and front wheel off. The calipers are also off the fork legs. It seems that the front brake hydraulic tube that runs through the steering head may need to be removed. If so, how does it come out? If it can stay in, what is the next step in getting to the bearings? What grease is recommended?

As always, thanks for any information.

Dr. Paul

You have to open the brake system to remove that pipe from the fork head. I has a "Y" at the bottom so comes out by disconnecting it from the top.

K75's have a rubber steering dampener inside the fork head. It's a rubber collar with a square waffle pattern inside which holds special silicone grease. Once you have pulled the steering stem out (from the bottom) you can remove the dampener by removing the two allen screws at either side of the fork head. BMW says to only use their special silicon grease to fill the "reservoir" spaces on the dampener.

When you put everything back together, you'll need to get the dampener aligned vertically so some of it's metal backing is exposed to the pointed ends of the allen screws. You leave the dampener loose while setting the fork bearing pre-load and only tighten the allen screws (thus "turning on" the dampener) after the preload is set.

BelRay makes an excellent high pressure water proof wheel bearing grease, but just about any good wheel bearing grease will work.

[DrPaul]

You have to open the brake system to remove that pipe from the fork head. I has a "Y" at the bottom so comes out by disconnecting it from the top.

K75's have a rubber steering dampener inside the fork head. It's a rubber collar with a square waffle pattern inside which holds special silicone grease. Once you have pulled the steering stem out (from the bottom) you can remove the dampener by removing the two allen screws at either side of the fork head. BMW says to only use their special silicon grease to fill the "reservoir" spaces on the dampener.

When you put everything back together, you'll need to get the dampener aligned vertically so some of it's metal backing is exposed to the pointed ends of the allen screws. You leave the dampener loose while setting the fork bearing pre-load and only tighten the allen screws (thus "turning on" the dampener) after the preload is set.

BelRay makes an excellent high pressure water proof wheel bearing grease, but just about any good wheel bearing grease will work.
Thanks, Greg. Does the brake fluid pipe pull straight out or unscrew? Mine seems pretty snug in there and doesn't want to budge.

Paul

[GregFeeler]

Thanks, Greg. Does the brake fluid pipe pull straight out or unscrew? Mine seems pretty snug in there and doesn't want to budge.

Paul

Once it's free at the top it should just pull out. Could be stuck with crud - maybe drizzle some WD40 down the sides?

[DrPaul]

Once it's free at the top it should just pull out. Could be stuck with crud - maybe drizzle some WD40 down the sides?I will try that. And thanks again!

Paul

[GregFeeler]

I will try that. And thanks again!

Paul

IIRC, the top of the "Y" at the bottom of that brake pipe had two tabs that lock into the bottom of the lower triple clamp, so you need to drive the pipe down 10cm or so to get those tabs out of their slots before you can try to twist it out.

[DrPaul]

Good Morning,
Received new fuel pump, vibration damper and filter yesterday and began installation last night when I discovered that the fuel level sensor/sending unit (which also routes power to the fuel pump) was totally shot. It is a VDO part and was wondering if anyone might have a spare or know of a source for this item.

I addition to the above parts, I now have new tires and the radiator fan unit in. I luckily found (thanks Lee!) a rear brake master cylinder on eBay. Also, I was able to get a used but clean looking fuel rail and injector set. So, things are gathering up pretty well and it won't be long (if I can quit finding things needing replacement) before she can go back together. As always, thanks!

Paul

[jdiaz]

Good Morning,
Received new fuel pump, vibration damper and filter yesterday and began installation last night when I discovered that the fuel level sensor/sending unit (which also routes power to the fuel pump) was totally shot. It is a VDO part and was wondering if anyone might have a spare or know of a source for this item.


Don't take a risk. Spend the $100 and buy a new one. I just did the same thing.

[DrPaul]

Don't take a risk. Spend the $100 and buy a new one. I just did the same thing.Good advice, I think. It is such a delicate part there are many opportunities for unknown damage to a used one. It's ordered from BikeBandit. I like them.

Got the steering head apart, bearings cleaned and lubed and all back together. The grease on the lower roller bearing had turned to hardened gunk. It's smooth as silk now. Got the radiator fan mounted and the radiator back on no problem. Plan to pull the FD back from the swing arm today to remove and lube the drive shaft splines. Any trick to reinstalling the tranny end of the shaft?

The only remaining fuel system component that has not been cleaned, replaced or repaired is the fuel pressure regulator. I'm sure it was exposed to the same fuel stagnation problems as the rest of the system. Any way to clean and test prior to reassembling everything? Maybe just replace now??

Paul

[hortok]

Congrats on the find!

RE: fuel. Run only premium. My '95 K75RT was very picky about fuel and would sputter and pop for a whole tank if I put anything less in it. I made a habit of buying my gas via credit card from a major brand name because a tank of the bad stuff was such a pain.

[PHMarvin]

Congrats on the find!

RE: fuel. Run only premium. My '95 K75RT was very picky about fuel and would sputter and pop for a whole tank if I put anything less in it. I made a habit of buying my gas via credit card from a major brand name because a tank of the bad stuff was such a pain.

My opinion of the above is BULLSH*T, BS, KAKA DEL TORO, and whatever other expletives one desires. HIS bike may have had a problem. However, the bike has a 10.2 compression ratio and will run fine on regular unleaded fuel. I've had 3 K75bikes - a '95 K75, a '95 K75RT and a '94 K75. None pinged at all while running regular, and out here, regular is generally 86 octane (R+M)/2. Maybe, if your timing is advanced, might you hear a ping or 2 in the hottest summer months, but here in El Paso (regularly 105F+ in June), I've never heard a ping out of any of my K-bikes, ever.

[Kayseventyfive]

From wikipedia:

……..In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-95 (regular) in Europe. …………………….

note: My BMW handbook calls for 91 octane.

[jdiaz]

My bike has always run fine on the lowest US fuel grades available, but it sure liked whatever was coming out of the pumps in Europe!

My knees would buckle if I stood behind my bike for more than 20 seconds while it was idling at the Agip station. :laugh

[DrPaul]

The only remaining fuel system component that has not been cleaned, replaced or repaired is the fuel pressure regulator. I'm sure it was exposed to the same fuel stagnation problems as the rest of the system. Any way to clean and test prior to reassembling everything? Maybe just replace now??Drive shaft removed without difficulty. Splines are perfect. The grease on the rear spline was a bit hardened but the front spline lube looked new. Found the Moly 60 at my local Honda shop. Should get relubed and back in today.

Still wondering if anyone has information on cleaning or testing the fuel pressure regulator. It's a $100 so would like to salvage if possible. Thanks!

Paul

[monkeywork]

I just love my K.

congrats!
http://farm2.static.flickr.com/1371/1331115280_b0ca33d5c5.jpg

[Kayseventyfive]

Still wondering if anyone has information on cleaning or testing the fuel pressure regulator. It's a $100 so would like to salvage if possible. Thanks!

Paul

The regulator can be tested by reading fuel pressure with a tee arrangement as shown in both Clymer and Haynes. It can be cleaned by use of a good fuel cleaner, such as Red Line (my fave) or Seafoam.

On one instance, I had low pressure and did this and that, finally removing the regulator for bench testing with compressed air. My testing showed no problem, so I scratched my head and put it all back together, whereopon it ran perfectly. I can only assume that the compressed air blew out a bit of swarf from inside the regulator that was holding the poppet valve partially open.

So.............from all that, a hundred pounds of air could help you be sure it is clean. I also found the Oetiker clamps on the lines on the regulator to be loose, allowing the hoses to be easily pulled off. The fire possibilities are a little frightening there. I replaced them with NAPA fuel injection clamps, which are checked for tightness yearly, owing to the heat accumulation there in summer traffic. New hoses, too.

Did I say I worship at the altar of regular use of a good fuel system cleaner?

[DrPaul]

Did I say I worship at the altar of regular use of a good fuel system cleaner?Chevron Techron Forever!
Thanks for the advice on cleaning and testing the regulator. I will do that this weekend.

Paul

[GregFeeler]

Chevron Techron Forever!
Thanks for the advice on cleaning and testing the regulator. I will do that this weekend.

Paul

Techron rocks! I always use Chevron gas, and now Texaco has Techron. I also run a tank treated richly with the Techron additive before every oil change. I've done this on all my vehicles (cars & bikes) for many years and I just never have fuel system problems. :thumb :thumb

[jdiaz]

My bike has seen one treatment of Techron in 18 years, and lives on 10% ethanol-based fuel. Never had a fuel issue of any kind.

The only thing that seems to stop these bikes is parking them. :D

[Kayseventyfive]

Techron rocks! I always use Chevron gas, and now Texaco has Techron. I also run a tank treated richly with the Techron additive before every oil change. I've done this on all my vehicles (cars & bikes) for many years and I just never have fuel system problems. :thumb :thumb

Techron......yeah, it is popular. And pretty good, too.

Back in the late sixties or early seventies, I commuted on a Vespa GS, and it liked its carb boiled every so often. Yes, boiled. In a pan of water with some Spic and Span on the stove. Just like Grampa did to the Model T updraft carb. It went longer between boiling when I burned Chevron gas. Yes, really. The ingredient advertised was called F-310, but names are names, and usually come from the ad department. It was based on a polybutene amine and was later named Techrolene, then Techron. They had TV commercials touting how clean engines ran on it, using an astronaut and a plastic bag. :)

[henzilla]

Techron rocks! I always use Chevron gas, and now Texaco has Techron. I also run a tank treated richly with the Techron additive before every oil change. I've done this on all my vehicles (cars & bikes) for many years and I just never have fuel system problems. :thumb :thumb

I have wondered about who's gas has the additive...we have a large gasoline terminal east of town, and we were replacing utility poles nearby one afternoon. An Exxon, Texaco, Shell, Diamond Shamrock, then a Citgo tanker ALL pulled in to same bay as we worked. There is a large gasoline producing refinery in the Texas City complex 300 miles away that produces for several brand names. ...Trying to remember the name, Marathon maybe. It is not one of the biggies. I worked for Exxon in the early 70's, and know they also refine gas at some of their facilities as do the others, but makes you go HMMMMM?

[DrPaul]

Removed fuel regulator and pressure tested. It pops off at 45 - 50 psi as best as I can tell with my air compressor gauge. It seems real clean inside so it will go back on. It appears the pop off pressure is controlled by intake vacuum off the #3 TB. I'm guessing that as RPM increases, the corespondent vacuum increase tells the regulator to maintain higher fuel rail pressure. Or, I could be wrong ..... :scratch
Paul

[Kayseventyfive]

Removed fuel regulator and pressure tested. It pops off at 45 - 50 psi as best as I can tell with my air compressor gauge. It seems real clean inside so it will go back on. It appears the pop off pressure is controlled by intake vacuum off the #3 TB. I'm guessing that as RPM increases, the corespondent vacuum increase tells the regulator to maintain higher fuel rail pressure. Or, I could be wrong ..... :scratch
Paul

How does it test on the bike?

[Kayseventyfive]

I worked for Exxon in the early 70's, and know they also refine gas at some of their facilities as do the others, but makes you go HMMMMM?

The Official Story is that it is the additive package that differentiates each brand. We have a major refinery in our community, and many of my neighbors work there, so I will do a little asking re this specific topic. I do know most of the tankers leaving are not brand marked.

[CustomSarge]

the vacuum port does open up the regulator to dump pressure on high vacuum I.E. snapping to idle. It is one of the ways to relieve rail pressure before service, for those who don't like VOC baths.

Did the rail/injectors test out well? Those with no hobbies want to know... <<<)))

[DrPaul]

How does it test on the bike?Dunno yet. The bike was parked 17 years ago with gas in the tank. When I acquired the bike, the seller had recently had the tank cleaned but nearly every fuel system component from the pump to the injector nozzels was shot. I've replaced the fuel pump, filter, in-tank lines, rail and injectors. Fortunately, I was able to get most of these parts on eBay or from Beemer Boneyard. I'm still waiting on the fuel level sending unit to arrive and then I'll be ready to put her back together. I have no reason to believe the ignition system will be a problem. In fact, I'm pretty sure it will fire up on the first touch of the starter button :whistle

Paul

[DrPaul]

It is one of the ways to relieve rail pressure before service, for those who don't like VOC baths.
Say again, Sarge. VOC bath???

Paul

[DrPaul]

Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?

Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.

Paul

[deilenberger]

Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?
Someone might be able to heliarc weld it - but I'd suggest doing a search on gasoline resistant epoxy - there are some products made for this use. Use it on the iside of the tank and you'll get away without repainting. The reason for the leak was water in the fuel - condensed from the atmosphere. It causes corrosion in the lowest point - usually the rearmost corners by the seams.

Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.
Normal. It's working correctly - the pump doesn't spin up with the ignition.. only with the starter and then when the engine is running.
Paul

[PGlaves]

Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?

Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.

Paul

Don has a good idea about the leak. Any decent auto parts store sells a gas tank putty that is a cylinder shaped piece of goop that has an inner part and an outer part kinda like a corn dog. You cut of a slice and knead it until it is a uniform gray color. At that point it is a bit sticky and can be pressed onto the leaky spot. Clean metal works best. If you put it on from the outside eventually (2 to 5 years) fuel will seep under the paint unless you wire brush it back away from the patch. Most such leaks are pretty well hidden even of not repainted - especially if on the inside rather that the outside of the bottom seam.

And for the curious, yes, I have used it on a 1987 K75S that is at my son-in-law's house and not ridden as much as desirable. It lasted about 3 years and then I redid it because I had put the original patch over the paint. Never needed it on Old Smokey but she got ridden frequently and water in the gas and the resultant corrosion was never a problem on that bike. But the 19 year old 30K miles K75S is a different story.

[Paul_F]

I have just ordered a small amount of paint (POR 15) to cover some minor rust on my frame. They have a gas tank repair kit as well. I got this information from a recent airhead rust thread.
http://www.marine-paint.com/merchant.mvc?Screen=PROD&Product_Code=CTRK&Category_Code=TankSealers

[deilenberger]

I have just ordered a small amount of paint (POR 15) to cover some minor rust on my frame. They have a gas tank repair kit as well. I got this information from a recent airhead rust thread.
http://www.marine-paint.com/merchant.mvc?Screen=PROD&Product_Code=CTRK&Category_Code=TankSealersThe POR kit really isn't suitable for a K bike tank (which has fixed lines inside the tank.. and the vent assembly.) The POR kit is a pour it in - and move the tank around so the liquid coats the entire inside of the tank. It would be good on something like an Airhead tank since there aren't fixed pipes/fittings in the tanks. Using POR on a K bike tank is very likely to plug up the vent fitting at the top of the tank.. making it useless, which will fix the problem since you'll be looking for a new tank after using it.

I'll repeat - an epoxy patch should work fine. I know of quite a few K bikes running around with one. As Paul noted - inside is better, unless you can remove all the paint in the area of the leak on the outside.

[BuddingGeezer]

I have repaired 3 pinhole seam leaks on my '87 K100LT. I ground with a Dremmel tool to remove paint and scuff the aluminum. I used 4 minute JB Weld. This has held for 13 months, 12,000 miles with temperature extremes of 15-110 degrees.

I painted the entire bike, so the color did not matter.

Ralph Sims

[DrPaul]

Someone might be able to heliarc weld it - but I'd suggest doing a search on gasoline resistant epoxy - there are some products made for this use. Use it on the iside of the tank and you'll get away without repainting. The reason for the leak was water in the fuel - condensed from the atmosphere. It causes corrosion in the lowest point - usually the rearmost corners by the seams.

Normal. It's working correctly - the pump doesn't spin up with the ignition.. only with the starter and then when the engine is running.Don, thanks for the great advice. I'm glad to hear my fuel pump circuit seems to be behaving normally. I like the idea of a fuel-resistant epoxy product. I'll look into that.

Paul

[DrPaul]

I have repaired 3 pinhole seam leaks on my '87 K100LT. I ground with a Dremmel tool to remove paint and scuff the aluminum. I used 4 minute JB Weld. This has held for 13 months, 12,000 miles with temperature extremes of 15-110 degrees.Ralph,
Did you put the JB Weld inside or outside the tank?
Paul

[BuddingGeezer]

Ralph,
Did you put the JB Weld inside or outside the tank?
Paul

2 of the holes were directly on each side of the other on the lower seam by the seat on the left side. The guy I bought the bike from had let it sit for 3 years on the side stand. I initially used the epoxy putty (CarGo) and I still had a leak. Then JB Weld, still wet, then Seal All, still wet. I ground all off and used JB Weld 4 minute, Still wet. I found another leak further up the seam. The paint was covering the hole.

I enlarged the holes to about a 8 penny nail in size, slightly indented the holes, ground the paint and aluminum with a Dremmel tool and applied the JB Weld. Sanded the JB Weld to conform to the tank.

The tank was empty, but not washed.

All is exterior. As I stated in earlier post, no problems, no leaks.

If the leak is at the lowest part of the tank by the seat, used only a small amount and the side cover will cover the repair, if you don't want to repaint. If someone is looking that close, tell them to get the hell away.

I had left side fairing repair and did not like the original color, so I repainted.

The putty you pinch and kneed will work, but the JB Weld will make a smoother and stronger , and bettler looking repair. Just make sure the metal is rough, even 60-100 grit, before you apply the JB Weld.

Ralph Sims

[DrPaul]

I have just ordered a small amount of paint (POR 15) to cover some minor rust on my frame. They have a gas tank repair kit as well. I got this information from a recent airhead rust thread.
http://www.marine-paint.com/merchant.mvc?Screen=PROD&Product_Code=CTRK&Category_Code=TankSealersPaul,
Thanks for the lead on this product. I'll check it out.

Paul

[DrPaul]

2 of the holes were directly on each side of the other on the lower seam by the seat on the left side. The guy I bought the bike from had let it sit for 3 years on the side stand. I initially used the epoxy putty (CarGo) and I still had a leak. Then JB Weld, still wet, then Seal All, still wet. I ground all off and used JB Weld 4 minute, Still wet. I found another leak further up the seam. The paint was covering the hole.

I enlarged the holes to about a 8 penny nail in size, slightly indented the holes, ground the paint and aluminum with a Dremmel tool and applied the JB Weld. Sanded the JB Weld to conform to the tank.

The tank was empty, but not washed.

All is exterior. As I stated in earlier post, no problems, no leaks.

If the leak is at the lowest part of the tank by the seat, used only a small amount and the side cover will cover the repair, if you don't want to repaint. If someone is looking that close, tell them to get the hell away.

I had left side fairing repair and did not like the original color, so I repainted.

The putty you pinch and kneed will work, but the JB Weld will make a smoother and stronger , and bettler looking repair. Just make sure the metal is rough, even 60-100 grit, before you apply the JB Weld.

Ralph SimsThanks, Ralph. The info is much appreciated. I plan to tackle the leak today so will post later on my results.
Paul

[DrPaul]

I'm feeling a bit like Baron von Frankenstein! As you know, my fuel tank had a small perforation on the left side at the lowest point from sitting on the side stand for 17 years with 1989 gas in the tank. I followed the advice from my BMWMOA friends and used the JB WaterWeld putty on the inside of the tank and the JB Weld Quick on the outside. These products are amazing. Hard as steel and absolutely no leaking. I filled the tank with regular unleaded, hit the starter button and the old K75S fired right off as soon as the pump had loaded the injectors! Quite a bit of smoke from all the Marvel Mystery Oil I had squirted into the cylinders a few weeks back but this cleared after a few minutes. As that began to clear, I rode her about 7 miles (it's 28 degrees here) and she ran smooth as silk! I'm amazed that a motor that has sat for 17 years can run like new! Everything works! All lights, signals, gauges, no problems whatsoever. She is quick, nimble, quiet and smooth. Thanks to all who have given sage advice on this project. Now, I'll get all the Tupperware back on and wait for fair weather to ride her more! I'll get pics posted ASAP.

Paul

[deilenberger]

I'm feeling a bit like Baron von Frankenstein!
Snippage..
I'm amazed that a motor that has sat for 17 years can run like new! Everything works! All lights, signals, gauges, no problems whatsoever. She is quick, nimble, quiet and smooth. Thanks to all who have given sage advice on this project. Now, I'll get all the Tupperware back on and wait for fair weather to ride her more! I'll get pics posted ASAP.

PaulPaul, VERY cool! :brad

I hope you yelled out "It LIVES! It LIVES!" when it came to life.. in the best FrankenCycle manner. I did many years ago when I brought an R65 that took a trip in the Atlantic Ocean back to life.. (a project I never want to even think of doing again..) :thumb :thumb :thumb

[jstanco]

Congrats on the find... Listen to the rest of these folks! They are awesome.. Your find has taught me a few things too..

[DrPaul]

My Clymers makes no mention of the significance of the ! within the triangle warning light between the green neutral light and the high beam indicator on this K75S. It came on just after filling the tank today. The bike seems to be running perfectly as far as I can tell. No ABS on this machine so I'm wondering what the light means. Anyone?

Paul

[bikerfish1100]

generally indicates a brake light failure warning. check the bulb first, then proceed to switches, etc.

[BuddingGeezer]

My Clymers makes no mention of the significance of the ! within the triangle warning light between the green neutral light and the high beam indicator on this K75S. It came on just after filling the tank today. The bike seems to be running perfectly as far as I can tell. No ABS on this machine so I'm wondering what the light means. Anyone?

Paul

This light is the rear light bulb check. If the tail light or brake light after engaging hand and foot brake pedal will not light, this light stays on. Check you bulbs in the tail light.

You cleared up for me on another post RosanaRosana Dana and said I was probably a little tike then. I was mistaken, but we are the same age 56.

Ralph Sims

[PHMarvin]

Hi, Paul,
The (!) within the red triangle is the brake warning light. It should go out after you use both your front brakes and rear brakes. If it stays on, it usually means you have a burned out taillight bulb or brakelight bulb. Even if they are on, change them. The warning light should then go out. If it doesn't, there may be a wiring problem and someone else can give you some further advice. When you change the bulb(s), I would advise using European bulbs instead of a brass colored base US bulb. The silver colored European bulbs seem to work better.

[DrPaul]

Thanks to all who posted on my /!\ indicator lamp function. Hmmm ... brake lamp or switch failure. And to think I was worried it might be something SERIOUS! :whistle

Paul

[Paul_F]

Mine will occasionally not go out unless I do some rather abrupt application of the brakes. Sometimes even that will not make it go out so then at the next stop I turn the bike off, restart, apply the brakes and voila, the red triangular light goes off. I had a dealer look at it once but it seems to be a gremlin that occasionally travels resides in my bike.

[DrPaul]

First decent day (clear, dry, almost 50 degrees) in a while here so took the "new" old girl out for a 50 mile shake-down cruise. I am fairly impressed; this is probably the smoothest, sweetest handling non-Japanese bike I've ridden in some time. The forward riding position would take some getting used to but, for the short hops, it's perfect! She makes my '02 R1150RT seem a bit rough. And to think she sat in a barn for 17 years without being started!

Well, I hope you enjoy the pics as much as I've enjoyed this project. I've still got the lower fairing off as I need to get some fiberglass work done on it; the shippers who delivered it to the PO must have used a belly strap to lift it onto the trailer and cracked the lower fairing in a couple of places. C'est la vie! (Actually, it looks pretty good without it!)

And again, thanks to all of you who have advised me on this project. Without your help, this would have been a LOT harder!

Dr. Paul

[DrPaul]

and another ...

[Paul_F]

Sweet.http://www.bmwmoa.org/forum/images/smilies/dance.gif
:dance

[deilenberger]

Big congrats on bringing it back to life! :)

[RayMCannon]

When I put it in gear on the center stand, the rear wheel sort of clicks. Is this normal? There is no indication of any problem while riding though. I use the bike almost everyday. 10,000 miles since a spline check, 40,000 on the bike now!
Thanks, R. Cannon

[deilenberger]

Normal. Just play being taken up in the various splines and gears.

[mrich12000]

:type Good reason to add Stabil Fuel stabaliser every winter's sleep.:german