Clutch Adjustment

[jeffcoatfilms]

I just had the clutch rebuilt on my 79 R65.  A few days after, I started stalling out when I came to a stop. Seems the adjustment bolt on the back of the transmission was slipping.

I tried resetting the tension on the bar adjustment to allow for the 201mm distance from the transmission to the clutch release arm.

When I went to adjust the freeplay from the back of the transmission I found that I had to have the lock-nut and the adjustment bolt all the way in to get some tension on the handlebar clutch lever.  Impossible to get the 2mm suggested distance, more like 5-10mm.  

It doesn't feel right, although it sort-of works...  Until it stars slipping again.

Seems to me that adjustment on the back of the transmission shouldn't be screwed in all the way.  

I'm relatively new to this, so any help/advice would be appreciated.  I'll probably be heading back to the mechanic but I live on an island and he's on the mainland so not so easy.

[Bob_Roller]

When you say you had the clutch rebuilt, is the clutch a replacement part, or was the friction lining replaced on the original clutch

[jeffcoatfilms]

That's a good question.  I know he said he had an issue with getting some parts, so some rebuild was necessary.  This guy works out of a garage, highly recommended and has worked on my bike before with good results and he's relatively inexpensive.  Problem is he writes his receipts on scraps he's got laying around in the shop -if you get one at all!  So no good record of what's been done other than him telling me and this time it was in one ear out the other.

 I'll follow up and find out.

[Bob_Roller]

I had the clutch disc relined and the two plates machined to true them up about 7 years ago for my '81 R65 .

When I got everything back together, I had the same issue that you have now, adjustment bolt all the way in and still not able to get the correct clutch adjustment .

I solved it, with a longer adjustment bolt at the back side of the transmission .

It's a standard metric size bolt, not a specialty part unique to the bike .

If you try this, don't get a bolt much more than 5 or so threads longer, you won't be able to get it started, it will hit the swingarm .

[jeffcoatfilms]

I was wondering if that may be an option! Seemed the most logical solution and great to hear it helped your bike.  I'm going to give it a shot.  Thank you!

[montmil]

Airhead clutch cable adjustments should begin at the transmission rather than the adjuster on the clutch lever. Starting topside can be an exercise in frustration.

Check the FAQs section -on page two, IIRC- for the R65 Owners Manual. Your '79 model should, I think, utilize the same adjustment technique as the later models discussed in the manual.

[jeffcoatfilms]

In my R65 Manual it says to adjust the Cable on the bar before the adjustment on the transmission.  

As far as I understand, the Bar adjustment needs to set the 201mm distance from gearbox to adjustment arm and that's it.  Basically to create the best angle for puling the cable.  Mess with that too much and you're creating extra tension on your cable and are more likely to snap it.

The free-play adjustment should be done at the transmission with the adjustment bolt. My problem being it seems my adjustment bolt is not long enough to give me the latitude I need for a proper adjustment.

Is it as simple as screwing it out to replace?  It tightens up towards the end and I'm worried there may be something else I should loosen up before it comes out? Or can I just keep going to twist it out?

[Bob_Roller]

You have a steel bolt threaded into an aluminum arm, steel always wins .

The end of the adjustment bolt may have been mushroomed on the surface that contacts the pushrod .

If it were me, I would remove the arm and check the bolt, before you damage the arm .

Also, remove the clamp that holds the rubber boot on the arm and transmission, break the boot loose from the transmission before removing the bolt that holds the arm to the transmission, if you don't do this, there's a chance you may tear the rubber boot .

[Luca]

After you've removed the clutch arm, screw the bolt all the way in and try cleaning it up with a nut or a die, or cut the end of the bolt off cleanly.

You are spot on with the adjustment.  The bar adjustment done first sets the cable length and thus the arm angle.  Once that's set, the bolt in the clutch arm sets the engagement point and thus the free-play at the lever.

As for the bolt backing out and ruining your adjustment, it should have a jam nut on it that you screw down against the clutch arm to lock everything in place when things are set.  Item number 9 in the fiche: http://www.realoem.com/bmw/showparts.do?model=0363&mospid=51897&btnr=21_0069&hg=21&fg=51

[jeffcoatfilms]

Yep, I've got the lock nut on there and the adjustment bolt is right up against it, both up against the gearbox.  I've got the 79 R65, so my set-up is slightly different than the one pointed to in the previous post which is for 81 and up.

I spoke to my mechanic briefly yesterday and apparently I had a loose pin that caused issues before. He's not sure what it is this time since it's an R65 and he usually works on the more popular older airheads, couldn't diagnose over the phone.  He's not very fond of the R65's and their 'uniqueness.'

I'll try and get the arm off today to have a closer look.

[Barry]

I checked my 79 to see how much adjustment there was available at the operating arm. With everything correctly adjusted I measure 4 mm of thread remaining. That's with all original components but only 20,000 miles from new. The locknut is really quite slim and if that were to be replaced by a nut of normal thickness the 4mm would be all but gone.

Seems to me it wouldn't take much wear in the clutch or some part of the operating mechanism to lose that 4 mm.

[Luca]

The link goes to a pre-81 diagram with the external spring...  

but anywho, I'd be a little wary of the mechanic.  All the clutch parts are available for these bikes from multiple sources and there is nothing unique about the R65 transmission.  It's the same transmission with the same clutch arm and throwout parts used in the bigger airheads.  Only the clutch/flywheel are different.

[montmil]

Was a measurement taken of the resurfaced friction disc to confirm the material is still greater than the minimum operating specifications?

As the manual's cable adjust technique is not working for you, you have nothing to lose by attempting to set the clutch actuating arm and the adjustment bolt first. If that doesn't work and a different length bolt doesn't correct the issue, you may need to have the mechanic give you a do-over. Gearbox on your R65 is not unique to the model.

[jeffcoatfilms]

Thanks everyone.  Really appreciate the input.  

Unless I get courageous this weekend and take it apart,  I'll probably bring it back for a do-over.  Which means leaving it, which means not riding it in some prime summer weather.  

[jeffcoatfilms]

D'oh!  Luca, you're right, that was the right link you sent.  I've been looking at too many diagrams.  Thanks!