grinding gears...

[Patrick_Krivacka]

on down shifts. seems I read that a misadjusted clutch cable can cause this. seems I also read that the haynes manuals method for adjusting the cable isn't right. can anyone lay out the procedure for me? or provide a helpful link?

[Rob Valdez 79 R65]

Adjusting the clutch:



From the Riders Manual:  http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?action=downloadfile;file=R65OwnersManual.pdf

[Patrick_Krivacka]

thanks rob. I'll give it a try and report back.

[Patrick_Krivacka]

I was going to do the clutch adjustment last night, but before I got started, I read through the info Rob posted one more time, and realized I didn't really understand it. Are they saying adjust the clearance at the gear box with the adjuster at the handle bars and vice-versa? whats meant by C=201+2 mm? and 2+0.5 mm? Does C=203mm and if so why didn't they just say that? 2+0.5 mm? 2.5mm?

[Bengt_Phorqs]

iman, is your gears actually "grinding" or are you getting a rather noticeable "clunk" when downshifting?  If it's the clunk that is fairly typical of BMW tranny's.  I've read and heard that attention to the transmission shims can help that.  Never having opened a tranny I can't personnaly speak to that.  

I've owned and ridden quite a few BMW's over the years and almost without exception that is a frequent complaint about the 'box-o-rox' transmissions.  About the only way I know of to deal with the clunk is to preload the shift lever, rev the engine slightly, then make the downshift.  It helps a little.

[Barry]

Are they saying adjust the clearance at the gear box with the adjuster at the handle bars and vice-versa?

Yes it sounds a bit odd but that's the way to do it and by far the easiest method of mearsuring the 201 mm is to cut a piece of welding rod or similar to that exact length

C=201+2 mm? and 2+0.5 mm?  

They are just tolerances and not that critical to the exact mm in my experience. The 201 - 203mm is aiming to get the clutch operating arm close to the maximum mechanical advantage angle of 90 Deg once the initial slack (2 - 2.5 mm) at the handlebar lever is taken up.

One thing that confused me initially is exactly where the 201 mm measurement is taken from. Is it the centre of the cable barrel nipple or the edge of the operating arm. The latter is correct however I didn't notice any great difference measured the other way. Coming to an airhead from other bikes it was a bit odd to have the clutch take up point right at the end of the lever travel and I was initially inclined to allow more than the 2mm slack. That was a mistake and I soon learnt to set it right and got used to it.

[Patrick_Krivacka]

It does clunk, but I'm familiar with that 'problem' in airheads. I sometimes get a bit of grinding, usually from 3rd to 2nd and 2nd to first. If I keep the rev's up then that will mostly do the trick, but it still happens occasionally, even with the rev's up. It's always on downshifts.   i read somewhere that grinding in the lower gears during downshifts is a sign of a mis-adjusted clutch. I would not be shocked to learn I'm wrong about that.

[Barry]

Quiet upward changes are easy enough and downwards 5th to 4th is usually smooth too because there is not a great difference in the ratios. Lower down the box the gaps between the ratios are much bigger therefore smooth quiet changes are harder and require some blipping of the throttle. I can do it well when pressing on a bit at highish revs but it's more difficult at slower speeds. It used to bother me until I got used to it.
Grinding can be a sign of too much slack in the clutch adjustment.

[Patrick_Krivacka]

thanks barry. I didn't see your post after bengt phorqs. you answered all of my questions (for now). I'll give it a shot tonight, thanks again.

[nhmaf]

Also, if you aren't going for a 100% original manufacturer restoration, our moderator Justin B has an excellent shift linkage (with HEIM joints and not bent pieces of wire) that definitely help the shifting experience.   I've got one on my R65 and it definitely works better than the stock part (no slop) IMHO.