The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: badgertom on May 07, 2013, 09:39:13 AM

Title: Possible clutch problems
Post by: badgertom on May 07, 2013, 09:39:13 AM
I ride a 1982 R65. Taking the bike out the first time this year I noticed that when shifting the bike sometimes would "slip" out of gear, or I have difficulty getting the bike into gear. This is my first bike with a "dry" clutch. Are these clutches more "sensative" or do I have a problem with the clutch. It can be dangerous when attempting to accelerate the bike pops out of gear. Also, how difficult is it to get to and repair the clutch. I understand the battery, carbs, and transmission have to be removed...some job ? Thanks for any suggestions or advice.  
Title: Re: Possible clutch problems
Post by: donbmw on May 07, 2013, 10:38:59 AM
http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1339637883

Check this link out. When was the last time your splines were lubed. and check cable free play first.

Title: Re: Possible clutch problems
Post by: Bob_Roller on May 07, 2013, 11:27:23 AM
A quick check for the clutch cable adjustment, you should have free play at the arm on the back of the transmission before the clutch is moved, usually a couple of mm .

At the clutch lever, you should have 2-3 mm free play  before the cable is moved .

Check the cable where it is attached to the clutch lever on the handlebar, it frays here at times and causes problems .

Check the linkage between the gear selector pedal and the arm that goes into the transmission .

The gear selector pedal can develop 'slop' where it is bolted to the foot rest support .

If all of these are good, you need to lube the transmission input splines like Don has said already .
Title: Re: Possible clutch problems
Post by: Luca on May 07, 2013, 01:24:22 PM
An improperly lubed clutch spline or improper clutch adjustment can cause trouble shifting gears, but it won't make your bike pop out of gear.

Even with a good clutch these transmissions can be a little tricky because BMW specified very tight driveline tolerances (Getrag of Porsche, Maserati, Alfa, etc. fame was making their transmissions by 82...) so as to minimise driveline slop.

The tight tolerances make it difficult to engage the gears, especially since our dry clutches do not drag when disengaged, like a wet clutch.

Therefore, if the bike doesn't want to go into first gear and the clutch is in good order, either roll it a little until you can get first in, or release the clutch and re-apply it before trying again.  Furthermore, because the tight tolerances make the transmission difficult to shift, Getrag made a two-stepped dog--the first step of the dog is a looser fit to facilitate "finding" a gear.  The bike will drive on that first step, but under load it can pop out of gear and you will find yourself in a "false neutral."  Not good for you or your transmission.

The fix:  Whenever you shift gears, keep your foot on the lever until after you have let the clutch fully out.  If by chance you didn't fully engage the gear you wanted, you will actually feel it in the shift lever as it moves further up/down when the clutch starts to drag and the gear and dog align properly and fully mesh.
Title: Re: Possible clutch problems
Post by: montmil on May 07, 2013, 06:00:38 PM
Nice post, Luca. Good advice.

These classic Airheads do require a certain shifting "technique."
Title: Re: Possible clutch problems
Post by: tvrla on May 08, 2013, 12:47:46 AM
As Luca says - I suspect your problem is the stepped dogs. I don't recall which gears have them - second and third? third and fourth? Something like that. Maybe all three?

One way to tell is that the shift lever won't come all the way up to the normal position if the dogs aren't all the way engaged. You'll get so you can feel that it didn't go far enough.