K75S shifting problem

[psych]

I have an '87 K75S with just over 60K miles. About 3K miles ago I started having problems downshifting from 5th to 4th. After a short while the same problem started with going from 4th to 3rd. I pull in on the clutch lever and push down on the shift pedal, but it doesn't want to move. I can FORCE the downshift, but I'm afraid I may damage something doing that. If I double clutch, it shifts smoothly. This problem shows up about 60% of the time, sometimes there's no problem apparent.
Can anyone give me an idea of where to start looking for the problem?
RBesecke@hotmail.com

[Eric1514]

Have you tried adjusting the clutch cable/clutch pushrod?

Eric

[kbasa]

When was the last time you had an input spline lube done?

[JohnHall]

Wouldn't the shifting be difficult in all gears if the splines were at fault. I don't know this as fact but it does not make sense to me unless I hear a good explanation.

[CustomSarge]

Different trannys have different tolerances & synchro behaviors. It's Usually the 3-2 downshift that points up a dry/sticky spline.
May Mr Eilenberger clarify the characteristics??? TIA... <<<)))

[deilenberger]

Different trannys have different tolerances & synchro behaviors. It's Usually the 3-2 downshift that points up a dry/sticky spline.
May Mr Eilenberger clarify the characteristics??? TIA... <<<)))
Actually - my dad, Mr. Eilenberger is 88 next week and no longer uses his computer.. but I'll try to fill in for him :)

If I was experiencing difficulty with a 4-3 shift or a 3-2 shift the first thoughts I'd have are clutch splines.. dunno why these two are the most probematical - but they are the usual harbengers of bad news on a K75.

If the clutch is correctly adjusted I'd be looking at:

Clutch splines - time to open it up and check for damage and if none is found, relube them with Honda Moly-60.

Shift forks - early K bikes had soft shift forks that tended to wear the shift drum and themselves. Fix is to replace them or find a good used trans. Eventually these will fail to the point the transmission cannot be shifted (BTDT wasn't any fun)

HTH,

[psych]

The splines and shift fork are going to be looked at, thanks for the ideas. If anyone knows of any unusual things that could be causing the problem or anything that the K75s are prone to, please post them.

[psych]

apparently the shift drum was worn in a strange spot and it was causing the transmission to "hang up" rather than shift smoothly. I've been out of town for the last 2 months, but I'll find out next week if she's really fixed.

[RichardCook]

Along the current theme, I have just started riding my new (to me) '87 K100RS after a thorough ($1000) going over at our Chicago BMW motorcycle dealer. [Replaced front and rear master cylinders and all the fluids. Otherwise a clean bill of health.] The bike has only about 1700 [sic] miles on it, having spent the majority of its life sitting in a guy's livingroom performing as an <i>objet d'arte</i>. When riding it I notice a distinct "ker-thunk" when shifting from 2nd to 1st. It is a rather loud, metallic sound that I can hear (and feel) quite clearly. It happens a fair amount of the time but not always. If I stop and clutch in neutral on the way to 1st it is much less pronounced. I have also had a couple of times when I missed shifting into a higher gear, e.g. 2nd to 3rd, and ended up in a neutral-like situation that could only be corrected by clutching again.

I'm a new rider and not at all familiar with what the bike should feel like so I don't know if this is normal or if I am sitting on a transmission breakdown-waiting-to-happen. The guys at the dealership who rode it didn't make any comments about it. It rides fine for me too and I can reduce the ker-thunking a good deal just by shifting from 2nd to neutral and then from neutral to 1st but is this something I should be doing?

Inquiring minds want to know &, as Bartles and James used to say, thanks for your support.

[deilenberger]

Along the current theme, I have just started riding my new (to me) '87 K100RS after a thorough ($1000) going over at our Chicago BMW motorcycle dealer. [Replaced front and rear master cylinders and all the fluids. Otherwise a clean bill of health.] The bike has only about 1700 [sic] miles on it, having spent the majority of its life sitting in a guy's livingroom performing as an <i>objet d'arte</i>. When riding it I notice a distinct "ker-thunk" when shifting from 2nd to 1st. It is a rather loud, metallic sound that I can hear (and feel) quite clearly. It happens a fair amount of the time but not always. If I stop and clutch in neutral on the way to 1st it is much less pronounced. I have also had a couple of times when I missed shifting into a higher gear, e.g. 2nd to 3rd, and ended up in a neutral-like situation that could only be corrected by clutching again.

The smooth shifting K bike transmission is famous for being one of Berlin's proudest products.. nary a word was said during press intro's back in 1983 about the agricultural nature of the transmission. Rare indeed was it to hear in a review of the K bike that the thing klunks and bangs around like a madman in a pot pantry..

I'm a new rider and not at all familiar with what the bike should feel like so I don't know if this is normal or if I am sitting on a transmission breakdown-waiting-to-happen. The guys at the dealership who rode it didn't make any comments about it. It rides fine for me too and I can reduce the ker-thunking a good deal just by shifting from 2nd to neutral and then from neutral to 1st but is this something I should be doing?

Actually - not. You do want to go from 2nd to 1st in one motion, and the converse - 1st to 2nd. What you may be doing is pulling the clutch ALL the way in and holding it. These fine examples of .. just don't seem to like that. Once my bike is moving, I rarely use more than 1/2 the clutch travel to shift. It's more just relieving pressure on the gears rather than disengaging the engine from the transmission.

The other technique a lot of people use - is preloading the shifter as they are pulling in the clutch. What his means is to put some light pressure on the shifter in the direction you want to go just as you start to pull in the clutch. This has the same effect as my 1/2 clutch (or 'feathering' as it is known..)

You may be surprised at times if you do preload by it actually shifting before you pull in the clutch - and it will do it perfectly smoothly with a complaint of any type.



Inquiring minds want to know &, as Bartles and James used to say, thanks for your support.

In case you didn't spot the tongue in my cheek - these tranmissions are known to be klunky. Shift technique can help it - but even those of us with bunches of miles on them do a klunk or a grind once in a while.

Luckily - they're actually quite sturdy, and the klunking and grinding don't seem to really hurt them at all provided you don't get carried away with it.

HTH,

[durangodoc]

I ride a 93 K75S (45,000 miles) and all signs are pointing towards these clutch splines being a problem. My Clymer manual disappointingly says (paraphrase), "This is a really complicated procedure. Have a shop do it." That's usually enough to scare me away, but it's a real pain to get the bike to a shop where I live.

What's a realistic expectation for time frame and cuss words if I do it myself, or should I just quit entertaining the idea and take it to the shop?

[PHMarvin]

Hi, Doc,
I am not a professional mechanic. I have done the spline lube on 2 K75's, both of them with ABS brakes. Both were done in my garage. Have someone there to help you. (For the first bike, my late wife helped; for the second it was my brother-in-law.) Figure that, for the first time, it will take a weekend. It's not particularly difficult, just time consuming. You basically start by working from the rear, removing the license plate holder and moving forward until you can remove the gearbox. There are a number of "How To" articles in the archives of IBMWR and probably here, too. I'm sure Don Eilenberger can help you find them.

[deilenberger]

Well worth reading:

http://www.ibmwr.org/ktech/clutch-spline-checklist.shtml This is what I would recommend, especially if it's the first time you've been in there. And some closeup photos of the splines on the transmission and clutch hub might help us give further advice on their condition. Unfortunately - this DIY doesn't go into detail or have photos.

http://www.ibmwr.org/ktech/clutch-spline-lube2.shtml and http://www.ibmwr.org/ktech/clutch-spline-lube1.shtml I wouldn't recommend so much. Problem with doing it this way - you don't get to actually see the splines well enough to judge the wear, and some greases have been found to be incompatible and turn to water when mixed. Doing it without full transmission removal almost guarantees some of the old grease will be left behind to contaminate the new grease.

The first procedure with complete removal of the transmission allows you to completely clean the splines - and apply new grease of a known quality. The actual difference in time isn't really a lot.

My favorite grease is Honda Moly-60 lube (made for Honda spline drives.) Paul Glaves mixes it with some Wurth-3000 grease and has good luck that way. The Wurth-3000 is the stickiest grease I've ever encountered, so chances are good it will stay on the splines and not get tossed off.

What we don't have is a good illustrated DIY for this project. If someone lives close enough to me (NJ shore area) and wants to do it - I might be able to give a hand (and I do have a lift which makes it MUCH easier to do) so I can take some decent photos of the process.

HTH,

[durangodoc]

Thanks for advice. I surely would have taken the easy road and followed one of the two articles you said not to. I like your reasoning for not doing that.

I think I'm going to give this a try. I've got more time than money and not much of either. I can always trailer it over to Basin Motorcycle Works in pieces if I have to. :laugh

[durangodoc]

I guess I jinxed myself with that last comment. This job was going along way too smoothly. It appears the problem is in the transmission. While I had the transmission off I decided to shift through all the gears to make sure it was operating smoothly. It is not. The problem (not shifting from 3rd to 2nd) is still there. It just binds up and will not go. So, I guess I'll carry my transmission into the shop on Thursday.:banghead

[bikerfish1100]

I guess I jinxed myself with that last comment. This job was going along way too smoothly. It appears the problem is in the transmission. While I had the transmission off I decided to shift through all the gears to make sure it was operating smoothly. It is not. The problem (not shifting from 3rd to 2nd) is still there. It just binds up and will not go. So, I guess I'll carry my transmission into the shop on Thursday.:banghead

heck of a lot cheaper to hand them a transmission and say "fix it" (or, "can you find me a low mileage replacement in known-to-be good ocndition?") than to give them your entire bike with the same words.

[chuck_donahue]

heck of a lot cheaper to hand them a transmission and say "fix it" (or, "can you find me a low mileage replacement in known-to-be good ocndition?") than to give them your entire bike with the same words.

I have a good trans you can have for $75.00 plus shipping from 60102. It does have a broken bolt from one of the foot peg brackets.

[babylter]

Durangodoc,
did you have the tranny looked at yet? Did you have the shaft turning when you
tried to shift it cause it most always is while on the bike ,running .
turning the shaft helps the gears to line up I think.
just a thought keith (blue95lt)

[durangodoc]

I dropped it off at the shop two weeks ago today. I carried it in and the mechanic gets a funny look on his face and says, "Did you want to ride again this year?" Ugh. Apparently there has been a rash of transmission problems here in southwest Colorado and there are 3 in front of mine. I did try turning the shaft while shifting, but that didn't help either. Oh well, that just means I can take my time putting the bike back together this winter.