Clutch Adjustment Problems

[JLThomas]

For all you technical and/or mechanical wizards out there, I have a clutch
problem that I would like some help with.

I have a 1981 R65. It has electronic ignition, and a light flyweight, so it's
one of the 'newer' build (although it does have dual ATE brakes, which I thought
were of the old build). It's now go 66,000 miles on the clock.

Last year I decided to give it a bit of TLC for its 25th birthday: new valves
and hardened seats for lead-free running; twin-plugging; and some diagnosis and
fixing for a slight oil leak from the hard to see area under the gearbox. No one
locally fitted the bill to do this (I live in South Wales), so I ended up taking
the bike to an ex-BMW engineer in the Midlands, who had a space to do this work
at a time when I had to go to the area anyway.

The oil leak turned out to be the seal between the engine and gearbox, so he
replaced that, and, as the clutch was worn right down, he replaced that as well.
I went back to collect it, and all seemed fine until I went to drive away, when
I found that no matter how hard I pulled on the clutch lever, I couldn't get
into 1st gear without stalling - the clutch would not fully engage (or is that
disengage - I'm never sure which way round that goes). We spent all afternoon
checking the lever, cable, the actuator arm, etc. He stripped out the 'easy'
bits from the back end of the gearbox, and ensured that the adjuster bolt was
the right one, and all the bits in the right order and orientation. We gave up
after 4 hours, and I went home by train.

2 weeks later I returned, by which time he'd stripped out the clutch again, and
replaced the clutch plates and the surrounding bits. The original clutch plate
he'd fitted, he said, was slightly thicker than the spec allowed for: he'd
fitted a slightly thinner one, but there was still a problem. The only way to
get the clutch fully engaged was to have the cable adjusted to the extent that
there was no longer any free play at the lever.

I think I should probably have stuck it out and left the machine with him again
at that point, but decided to take it back home, in the expectation that some
usage would settle things down and allow proper adjustment.

Over 6 months later (and around 8,000 miles on) it's still no better, in fact, it
may even be worse. I've checked the cable setup against the article in the BMW
Club journal (I think it was April 2006) and the setup matches - all except for
the 2mm freeplay at the lever.

Either the R65 setup is different from all the others, or there must be
something wrong within the pushrod to lever assembly. Can any of you give me any
pointers as to what may be wrong?

Thanks

[Bob_Roller]

There is an adjustment for the clutch at the gearbox, the arm that the cable hooks into, has a specific dimension from the gearbox that is adjusted by the adjustment bolt with the jam nut on it, I don't remember the dimension, but this is done before the final adjustment at the handlebar cable adjuster. If you have the original owners manual, I think there is a procedure in there to make this first adjustment. I'm sure others will be adding their knowledge of this shortly, as it's just about the end of the work day here in the US.

[Chris_in_BC]

What did you change with the clutch? Just clutch plate? or pressure plate as well?, spring? cover plate?

Did you change any parts in the actuation mechanism? Thrust bearing? Understand that 1981 bearing is no longer available and uses a different clutch push rod with a different bearing. Any possibility with mis-matched parts here? Just trying ideas.

The distance mentioned by Bob from the back of the gearbox to the point where cable rests in the actuator arm should be 201mm.


Just an aside your 1981 R65 with ATE brakes is normal.

[JLThomas]

I didn't do the changes myself, they were done by an ex-BMW engineer.

The clutch plate, cover plate and pressure plate were changed, but not the spring - I think. I don't think any of the actuating mechanism was changed.

The change in the actuating system in 1981 was part of the change to the lighter flywheel, and the 2 systems are incompatible. I don't think there's any way that he would have made a mistake like that.

When we started trying to sort it out on my first attempt at pick-up, we checked the 'open-cable' distance, and it was right at 201mm. It just seems that no matter how much we adjusted the push rod, it was impossible to get a combination where there was free play at the clutch lever, AND the clutch could be fully engaged - even a little freeplay meant that dropping into first gear was accompanied by a surge forwards.

I've just found my April 2006 edition of the UK BMW Club Journal, which has an article on clutch cable adjustment by Gary L. Smith. I'm going to follow his detailed instructions (with great diagrams as well - a real idiot's guide - perfect for me  ) and see if it comes up any different - I'll let you know the outcome.

Hopefully that'll work, but if not, I think I'll have to extract the pushrod assembly and inspect it, maybe something's given up in there - I hope that I can get the bits still.

Wish me luck.

[Ed Miller]

I'm not sure if this will help, but here goes anyway.  On MY '81 R65 I find that 2mm of free play to be almost impossible to feel.  The reason is that the coiled spring inside the clutch boot, behind the tranny, is always pushing out, and it's difficult for me to feel the difference between when I've collapsed that spring to zero free play, and when I'm actually engaging the clutch.  I've taken to using just one finger to pull on the clutch lever, and when that one finger can no longer pull the lever back any farther I think I'm starting to disengage the clutch itself.  That's with the stock clutch parts on my bike, by the way.  Here's a picture of them, from Snowbum's web site:



I set it that way, then if road testing says I have too much or too little, I'll fine tune it accordingly.

Your article should say this, but the 201 mm dimension is set with the clutch lever adjustor, and the 2mm free play is set with the adjustor at the back of the tranny.  Hey, I didn't design it....  You really need a picture to know where to measure that 201 mm.

Hope this helps,
Ed

[Chris_in_BC]

The change in the actuating system in 1981 was part of the change to the lighter flywheel, and the 2 systems are incompatible. I don't think there's any way that he would have made a mistake like that.

Hi, I wasn't talking about the changes between pre '81 and after '81 bikes. If you look at the Moto-Bins UK site and check out clutch pushrods, they mention that the original 1981 bearing and thrust piston is no longer available.  So does this new thrust bearing replace the two parts in the centre of Ed's picture? Do you need to change the push rod? Don't know.

 I would query it with Peter at Moto-Bins.

And all the bits for the R65 clutch are readily available... just have to make sure they are the right ones  

Part number 31821 on Motobins

[Ed Miller]

Tom Cutter sent me this part number for the upgrade:   23 13 1 464 167 but I haven't tried to order yet because my bearing looks fine and I usually replace throw out bearings (on cars and trucks) at the same time as I change clutch parts.  

The picture you posted looks like it would just use the original clutch push rod.
Ed

[Semper Gumby]

Hi JL,

Make sure that the clutch plate he replaced with was the 1981 on clutch plate.  BMW changed the R65 clutch at the end of 1980.  

Clutch adjustment procedure.

Make yourself a tool.  I used a piece of brass tubing.  It needs to be 203mm long.  This measures the distance from the flange where the clutch cable comes through the tranny housing to the actuating arm on the back of the engine.  Use the adjustment ON THE HANDLE BAR to set this distance.  Then go to the adjustment on the back of the engine undo the lock nut and adjust the nut on the back of the tranny until you have 2mm of freeplay on the clutch lever (Where it opens - where the cable hooks into the handle.  You now have a properly adjusted clutch.

Good luck.

OOps - i see ED is saying 201mm.  I may be disremembering so go to the owners manual.  The procedure is in there.  I'm on the road so I can't check mine.

Greetings from cold but plowed Boston MA.

[Chris_in_BC]

You are right Bill, 201mm +/- 2mm
And it is always confusing working from opposite ends. Using the handlebar adjustment to set that 201mm gap, then the clutch throwout to set the handlebar.  :-/

[JLThomas]

Thanks for all you help and advice. I've followed my idiot's guide as best as I can, and I think I have it set now. I don't think there's as much as 2mm of free-play, and the lever has to be pulled right back to the handlebars to clear the clutch. I found it really difficult to determine where the free-play starts, it's not a clearly defined point (as far as my experience today goes, anyway).

I ride the bike to work and back every day, so by this time tomorrow I'll know whether it's improved or not.

Will the distance between free-play and fully engaged increase or decrease with time?

[Chris_in_BC]

Note in the picture that the clutch actuator arm is angled back from the vertical away from the gearbox. They say it is supposed to be 4° off vertical. On my G/S (same arrangement as the R65) I find the adjustment bolt on the clutch arm is almost all the way in. There is almost no room for the lock nut there, to enable the arm to be angled back. Otherwise pulling in the clutch right to the handlebar was needed to disengage. (and even then it still drags a bit)
I have been wondering whether there is wear on the end of the clutch pushrod where it fits in the spring or wear on the hole in the spring itself. If the overall length of the clutch pushrod is shorter than what was intended, this might be causing the problem. So far I have been too cheap to get another pushrod to test out my theory. Although, really the adjustment bolt should be what accomodates any differences in length, so I could be out ot lunch in my thinking.

Good luck on your ride to work.

[JLThomas]

Today's ride in was fine - as far as the clutch adjustment went (another motorcyclist had an 'off' on my route down the M4 motorway, so a whole section was shut - he's in hospital, but I think is okay).

Clutch lever right in definitely engages the clutch okay, and the gears change okay, no creeping. It's difficult to tell still whether I've really got any free play, but I'll keep it as is for now.

Thanks for all the help.

[Ed Miller]

If it doesn't slip when you accelerate hard, you probably have some free play.  If it still gives you trouble later, I wonder if it would be possible to temporarily remove that spring in the middle of the picture I posted above, reassemble the rest of the parts, and adjust the free play.  It would be easy to feel without that spring pushing out on the rubber bellows.  Then, when the play is adjusted correctly, reinstall the spring without messing up the free play adjustment.

I'm thinking you could very carefully press the clutch lever (behind the tranny) to give you enough cable play to disconnect and reconnect the cable as needed.  You would need to be careful because that lever seems very fragile.  I've done it with a 1 x 4, between the lever and the frame rail behind the tranny.

Good luck,

[xeffer]

I came accross this old thread, and would like to ask something... the 201mm setting at the back of the clutch cable... I understand that this only applies to '81+ bikes. What would the setting/procedure be for bikes made before 1981? does anyone know? I'm still waiting for my workshop manual.

[Semper Gumby]

xeffer,

I use the same setting on and procedure on my 1980 and it works (really){old style clutch and flywheel with smaller 6mm screws into the flywheel.}  My tool for the "C" distance is a 203mm brass rod.  Set this distance with the handle bar adjustment.  Then set the 2mm freeplay on the bar with the "B" nut on the back of the tranny!!!!!  

[see tranny picture above]  Thanks Chris....

TTFN,