The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: jamestnewsonr65 on September 13, 2014, 03:47:18 PM
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So I took the bike out today for it's first run on a private road before I get it MOT'd and all was well, but as I ran it a couple more times I seemed to lose a bit of drive.
Revs are ok, but the speed does not really pick up through the gears. Could this be down to a slipping clutch or bad adjustment of the clutch arm?
This is the first time I have run the bike or indeed riden it, as when I bought it I started to strip it down immediately. Everything was fine before the rebuild and the engine has not been touched. Just the gearbox removed so the engine could come out.
I also fear that the oil distributor which is attached via the screw under the airbox may have come lose, but im not too sure how to check that one.
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I would put my money at the slipping clutch at the moment. If it does slip, it should be noticeable when you push the bike on 2nd or 3rd gear (not running). Push it, adjust the clutch arm to lesser degree and try to recognize any difference. While pushing, play with clutch as well.
And then start the bike and see if the problem still persists. I would even adjust the clutch to barely engage just to see if the revs+speed start to match.
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A slipping clutch should be quite evident in 2nd or 3rd gear when you go full throttle. Good hard acceleration with the "usual" revs should be the norm. Revs going high but road speed not picking up appropriately would indicate a mis-adjusted clutch cable, a cable that has faied inside the sheath and is not moving smoothly and/or a clutch that may be either worn below spec or has become oiled due to a seal leak.
Make the simple checks first. Disconnect the cable and confirm the cable is not boogered and binding. Confirm cable adjustment and clutch actuation arm. Then you may freely utter any blue language you choose as it's probably going to need a trans pull and clutch assembly inspection.
Luck to you. Report your findings.
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Im not sure if it is the clutch slipping as I have all new cables etc and it's been adjusted as per the clymer manual. I will check again this afternoon to see what happens and let you know.
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Forgot to say that the clutch was bone dry when I disassembled, but I have lubed the splines, but minimal lube in line with what is needed. I am loathed to have to disassemble again, but if it has to be done it has to be done.
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I tried pushing the bike in 2nd and 3rd and was still able to push it, which I guess means the clutch was slipping.
Adjusted the gap between the case and the clutch arm over the suggested size of 210mm, or whatever it is from memory, and it worked. Tried to push the bike again in 2nd/3rd and it wouldn't budge.
I took it out for a run and everything was much better, drive was restored in the gears and pulls. I can't believe how easy the venhill featherlight cables are to use!
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I also fear that the oil distributor which is attached via the screw under the airbox may have come lose, but im not too sure how to check that one.
Is this the 'tray' on the ceiling inside the gear box you are referring to?
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Yes that is the one.
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Lets have a picture of the finished article!
Cheers
Rev Light
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My 1981 R65 had a loose oil distributing pan inside the gearbox when I bought it. Ocassionally it could be heard clattering against the gears !!
Probably should be investigated further, to avoid a catastrophe. Sorry I don't know how you could check this without opening up the gearbox.
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I have been a bit slack on the updates front. Will stick up some images today at some point.
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You might be able to get back to the 201mm by adjustment of the cable free play at the handle bar.
It sounds perverse but you set the 201mm by the knurled cable adjuster at the handle bar and you set cable free play by adjusting the screw at the gearbox cover. If you do it exactly as described in the handbook it should work.
If not it's no big deal as the whole process is only designed to gain maximum mechanical advantage for the clutch actuating lever by setting it parallel to the gearbox cover at half handle bar travel.
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I will try and get the distance back to 201mm. I did adjust everything as per the Clymer manual when I installed the new cables, but obviously my clutch has different ideas about working correctly.
Do you think this indicates a worn clutch at all?
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I would have thought it more likely to be a cable length issue.
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If the clutch was permanently engaged from being set too far in then you must have had no free play at the handlebar lever. Now that you've got it working, you should make sure that the lever has free play throughout the full range of steering motion.
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I adjusted the freeplay on the lever to achieve more distance on the arm, but this was just to see if it worked. I need to adjust it properly again before getting it MOT'd. Will go by the book and set the correct distance and freeplay again. At the moment it has too much freeplay and the distance is about 210mm from the case.