K75S Hard to Downshift Sometimes

[detbmw]

I bought my '88 K75S (55K miles) in September and immediately found that the drive splines were almost shot, and finally got it on the road again last week.

I have been trying to become Brick-Smart by surfing this forum and others and reading, reading, reading. I thought I read somewhere (maybe here) that if the bike will not downshift unless you cycle the clutch, it could be an indication that you really need to lube the clutch splines. Sometimes when I'm in fifth gear and I go to downshift, the lever does not move at all - it's rock solid. I release the clutch lever and re-engage the clutch, and then I can downshift.

I was thinking of doing a clutch spline lube sometime as I have no maintenance history on the bike. But I'm now thinking that I need to do it very soon.

What do you folks think?

[frankenduck]

Yep, probably time to lube the clutch splines.  The sooner the better because if they're dry then they're wearing every time you ride.

[detbmw]

I've only found one reference to parts needed, and that was on the ibmwr tech page. It was recommended to have exhaust manifold seals and kickstand console bolts. Is the exhaust manifold seal the gasket ring at the engine (11 62 7 662 083) or back at the muffler (8 12 1 457 142). And what is a kickstand console bolt?

[frankenduck]

The 18121457142 part.

Don't know on the kickstand bolt.  Have no idea what's up with that. :dunno2:

[detbmw]

The 18121457142 part.

Don't know on the kickstand bolt.  Have no idea what's up with that. :dunno2:

Opps, didn't copy the leading 1 from the Max BMW site - thanks! I need a couple other things so I will get that too.

[wmax351]

I just used some exhaust tape around the headers instead of the 142 gasket.

[frankenduck]

Probably works better than that $13 gasket.

[wmax351]

Probably works better than that $13 gasket.

Indeed. Tiger Tape. A couple layers, squeeze it into the muffler, and bolt it down. Smokes for a few minutes. Will probably be a pita to get off, but I can take the whole system off en bloc if I need to.

[detbmw]

I'm planning to start the clutch-spline lube Friday afternoon at my buddy Jeff's house. I'll post how it goes.

[ahimsa]

The reason they suggest replacing the bolts that hold the kickstand on when doing this job is that those bolts originally had a thread-locking compound (loctite equivalent) on them. So you could buy new bolts that come from Germany with loctite on them, or you could clean the old ones with a wire brush and apply new loctite to them yourself before installing them.

You can also re-use the old exhaust gasket... if it works, it works.

[552255]

There is a way to to do a quick(er) trans. input spline lube...the method of sliding the trans/shaft/wheel backward, and using a long small painters brush to apply the grease to the spline, thru the crack/opening of the bellhousing.  I have done it twice this way and it worked fine.   Used M10? longer bolts for 'guidepins' to slide the tranny back on (important)...its a difficult job no matter what, but removing the tranny completely i found to be way more work.  This way many 'linkages' can be moved/rotated/slid without actually removing them etc.

I figured the trans. input spline to be relatively sterile place, so adding some good moly grease to it was enough...and, to fully apply, rotate the rear wheel in gear, to turn the shaft...

[frankenduck]

M8

[detbmw]

The clutch splines had a red rest look to them, so I'm guessing it was the original BMW #10 grease on them, so they had probably never been lubed in 25 years. The o-ring from the engine output shaft was leaking, so we also replaced that. The clutch friction plate was in good shape. I might replace it in another 20K - 25K miles when we lube the splines again.

It was a real learning experience, it was a first time for me and the first time my buddy Jeff had done this on a brick.

[KJeff]

The clutch splines had a red rest look to them, so I'm guessing it was the original BMW #10 grease on them, so they had probably never been lubed in 25 years. The o-ring from the engine output shaft was leaking, so we also replaced that. The clutch friction plate was in good shape. I might replace it in another 20K - 25K miles when we lube the splines again.

It was a real learning experience, it was a first time for me and the first time my buddy Jeff had done this on a brick.

Did that fix the downshift problem ?

[detbmw]

The clutch splines had a red rest look to them, so I'm guessing it was the original BMW #10 grease on them, so they had probably never been lubed in 25 years. The o-ring from the engine output shaft was leaking, so we also replaced that. The clutch friction plate was in good shape. I might replace it in another 20K - 25K miles when we lube the splines again.

It was a real learning experience, it was a first time for me and the first time my buddy Jeff had done this on a brick.

Did that fix the downshift problem ?

Yes it did. The bike shifts like a hot knife through butter. I no longer have to worry whether or not the bike will downshift when I need it.

[ahimsa]

I did the same job on my K1100RS this past weekend, for the same reason (difficulty downshifting.)  I couldn't find any decently long M8 bolts at my local hardware stores, so I cut off a couple of 17cm-long pieces of M8 threaded rod to put in the lower bolt holes on which to slide the transmission back. I was able to get a 6cm gap between the bellhousing and the transmission, big enough to get a toothbrush in to clean the old stuff off the splines and put the new stuff (Honda Moly 60) on with my fingers, and the transmission slid right back in place with no hassle.

[detbmw]

I did the same job on my K1100RS this past weekend, for the same reason (difficulty downshifting.)  I couldn't find any decently long M8 bolts at my local hardware stores, so I cut off a couple of 17cm-long pieces of M8 threaded rod to put in the lower bolt holes on which to slide the transmission back. I was able to get a 6cm gap between the bellhousing and the transmission, big enough to get a toothbrush in to clean the old stuff off the splines and put the new stuff (Honda Moly 60) on with my fingers, and the transmission slid right back in place with no hassle.

We pulled my transmission all the way off. Then we saw the oil in the intermediate housing and ended up replacing the o-ring on the engine output shaft. I'm glad we did it all or the oil leak could have been a major problem later on.