Suggestions for starting my Black Brick?

[Paul_F]

Any ideas for starting my 1987 K100RT? Last November, three weeks ago and now last night, the same problem has occurred. The bike turned over and starts to run, but during its warmup time, it stalls. Then it refuses to start again. The electrics turn over and the acoustics sound as if the engine is on the verge of firing, but the engine does not catch. Oh, and if I try too many times, I do smell gasoline. I haven’t tried that hard this time. As well, the battery reads 13+ volts.

In November, my BMW mechanic said that it was an electrical problem. He also did a 20, 000 km service at this time and I wrapped it up for the winter. Three weeks ago the same scenario. He looked at it and said he found leaves in the gas tank and replace the plugs and the fuel filter. He also made a point of telling me that a bike with 140, 000 km (about 88, 000 miles) had a uncertain and limited life left. When I asked him about beemers with hundreds of thousands of miles, he told me it was mainly myth. Bikes that did make it that far either had everything replaced or they were held together by duct tape and wires.

The P.O. had all service done by a BMW dealer, as have I. I expect it to last longer than 140, 000 kilometres.

My dilemma is that I have just recently put out $ 300 for the last repair and had to borrow a trailer to take the bike 100 miles to get it working and now it is still sitting as a paperweight in my garage. I also am developing a fear of going very far on the bike in case it stops dead somewhere far away from home (if it should ever start).

All I want to do is to get back to riding with confidence that I can come home. Suggestions?

[Motorman]

I'd find another shop to work on it if that is their feeling.

It sounds like fuel starvation to me. Do you hear the fuel pump running when you try to start it?

Did you put it up for storage with gas in the tank? If so did you at least put stabil in it? If not, does the tank smell like varnish instead of gasoline?

If the answer to the last questions is yes you may have gummed up the fuel pump and or injectors. If the pump is frozen up it will likely have to be replaced. I tried to loosen up 2 and it didn't work with either pump and I used some heavy duty solvent. The pump for my K75 is over $300.00 US.

[Paul_F]

Can't say as I know what the fuel pump sounds like. Hence I really do not know if it is running or not. I do know that if try for too long trying to start it, I do smell gasoline. The mechanic replaced the sparks (after only 1700 km) because they were damaged because of being soaked with gasoline.

A fresh tank of gasoline was left in the tank for the winter, with fuel stablizer. I am now on my third tank of gasoline for this season. This problem first occurred in early November, before the bike was serviced and then stored for the season.

No I can not smell any varnish when I open the fuel tank.

The tech told me on my last visit that the fuel pump was not the problem. In Canada, for the K100, apparently a fuel pump runs close to $ 600.00. Ouch!

I am tempted to have a local Honda shop that does some work on beemers, trailer it to their shop and look at it. The reason I trailer the bike so far is that the local beemer shop has not been either competent with their servicing and have attitude servicing older bikes. Of course the 2nd BMW service seems to be lacking as well.

[Polarbear]

You said it started, ran for a few minutes and cut off,yes? Tank is not vented properly, so check this first. Always do the easiest tests first, I say. It usually comes out Aok using this approach. Mechanic has dirt between his ears, saying bike at this mileage is tired. He's been living in a cave! We only have 1000's of them running around this continent and others with more miles than this. Going strong! Try running your bike again with tank cap open to see if it continues running. Don't ride it this way(far),hehe. Well, this is easy start. Good luck,Randy

[roy]

Possible Hall effect sensor. They seem to fail when warm. Your initial posts says youe smell gas so it would seem that fuel is not the problem. If you have an inductive pick-up timing light check for spark while turning the bike over.

I believe there have been several write-ups on diagnosis and repair of thie sensor. It is located under the "T" shaped cover on lower right front of the engine.

[CustomSarge]

You mentioned the engine spins, but doesn't catch. Is it firing inconsistantly? Yes:fuel/plug fouling, no:ignition.

1> On a "stumbling" condition, I change plugs. I've had Ks that took 2-3 sets every spring before running right.

2> Momentarily push the starter. Listen for a "whirring" sound lasting 3-4 seconds. That is the fuel pump repressurizing the system. Do this a couple times, you can't over pressure it.

3> That it starts at all indicates pressure is first ok, but soon falls off. Since filter's changed & is after the pump, check the pump screen. Do #1> again. If the pump is still cycling, something is restricting flow. Look for any real amount of floating debris, it would tend to gather around the pump inlet screen, restricting flow.

I've seen where the tube style inlet screen didn't have a spring in it. The spring keeps it from collapsing and choking off the inlet.

I have a K11LT that slowly developed a hard-to-start. Eventually, highend power was also affected. Turned out, the previous fuel filter change (me!)had the hoses such that the filter rested against the corner of an internal slosh divider.
Said corner was sharp and cut several "slots", causing evermore gas to bleed out the filter and reduce system pressure. I pulled the cap, and laughed my tail off when the "fountain" was so obvious. Good Hunting... <<<)))

[godzilla]

I copied this from a previous thread becuase that is EXACTLY what my K did when the Hall Effect sensor went bad:

"Then it would start, but shut down and not restart for awhile, then finally kick in. My mechanic thought it was the Air Flow sensor gizmo thingy ma bob doohickey. He replaced that and it ran OK for a month, then started acting up. I would pinch off the hose on that thing and it would start, at least for awhile. Finally she died and wouldn't start no matter what. My mechanic is an R-kind of guy and did alot of cussing at the K bike while he shotgunned parts in and out, such as the coils and the computer. Finally he gave up and was going to call a K-bike guy. but before the K-bike guy got there, he replaced the Hall Effect sensor and that fixed the problem."

As for that statement that your K is on it's last legs and it's a myth that they 'run forever'? I have over 112K on my 85 K100 and she shows no signs of dying and needing some serious rebuild. None. My brother has an 85 K100RT and he doesn't even KNOW how many miles he has on her (broke speedometer), but it is close to 200K and he has never had it torn down.

I'm offended! :D

[cjack]

snip
As for that statement that your K is on it's last legs and it's a myth that they 'run forever'? I have over 112K on my 85 K100 and she shows no signs of dying and needing some serious rebuild. None. My brother has an 85 K100RT and he doesn't even KNOW how many miles he has on her (broke speedometer), but it is close to 200K and he has never had it torn down.

I'm offended! :D
Everytime I want to call someone a bozo, like that mechanic, I remember how nice and positive boxergrrlie's posts are. So I won't, but...
I met a guy yesterday from down around Evansville, IN on a '99 K12RS with 128K miles on it. No duct tape.

[tjtraver]

Sounds very similar to my K75 which had a Hall effect fail intermittantly .

Observation : I noticed that when the hall effect cut out, that my tach dropped immediately to zero, even though the ignition was on and the engine was being turned over by the rear wheel as I coasted to a stop.

Question : If that's what your tach does , I'd vote for bad hall effect.

Reccomendation : Pick up a known good used one ~$100 from the usual sources and swap yours out .

[PGlaves]

If you put in clean dry plugs it will start and run.

Then it may fuel foul the plugs again. The trick will be to troubleshoot the ignition sytem to see why it is losing spark and fouling plugs.

If the ignition system proves OK - then look at the fuel side to see why it might be going rich.