Clutch To Remove and Check or Not

[davidswanson]

I have my transmission out and normally with a car or truck I would automatically replace the Clutch at the same time. I thought initially that I would do this on my 1991 R100GS-PD but in reading the repair manual it started to seem like a big deal as you have to keep all the parts lined up for balancing purposes. Can any one advise on the pitfalls i face in opening up this can of worms? Right now my clutch is working fine but I am planing a long trip soon and I really would like to have certainity that my clutch is up to the trip.

swanny

[Isamemon]

not know ing if you have an original clutch or not or what your miles on the bike are
how often you ride two up
and your trips if your laded with gear or not
and of course your riding style

also dont know if you pulled the tranny yourself, and how soon you want to do that again soon
but if your paying some one to pull and replace
its not cheap
sure a new clutch is not cheap, but cheaper now with the tranny out, then in summer and paying to do it again

I myself, would replace the clutch and main seals also for me, then next time, Im gonna have the flywheel lightened ( you already have the light one)

[sgborgstrom]

An unabused airhead clutch will last for many 10s of thousands of miles before needing replacement. That having been said, it's not that hard to pull the clutch out now that you have it exposed and peace of mind goes a long way on the road.

It's been about 9 years since I last did an R&R on one of these (and it was an R75/6) so don't take this as the definitive answer.

IIRC you need some long bolts with spacers to relieve the tension on the assembly, a well stocked hardware store should be able to supply these. The tougher tool to source is the "re-alignment tool" used to get all the plates lined up so the input shaft from the tranny slides in. I managed to get away with not using one last time I pulled my K's clutch apart. Ask around, somebody near you might have one to lend. As for the alignment marks, use a paint pen and give yourself some marks to guide you.

[Rod Sheridan]

Hi, since removing, inspecting and measuring the clutch components will require less than an hour of your time, it would be foolish not to do it.

I perform this work everytime I remove the gearbox to lube the splines.

Regards, Rod.

[Motor31]

I'd pull it and replace it now since you have over 75% of the work done. CHeck with some automotive supply shops, you may be able to rent (or borrow) a pilot shaft to align the clutch assembly with the flywheel so the transmission shaft will mate properly. A pilot shaft is a common tool to use when replacing clutches on cars with standard trans. for the same purpose as on the bike.

[20774]

The tougher tool to source is the "re-alignment tool" used to get all the plates lined up so the input shaft from the tranny slides in. I managed to get away with not using one last time I pulled my K's clutch apart. Ask around, somebody near you might have one to lend.
I think you can get around needing an alignment tool...at least I did on my /2 and it should be essentially the same. Before you tighten down the screws that hold the clutch pack together, slip on the transmission enough to engage the clutch splines...even with the longer bolts in some of the screw holes. Then actuate the clutch and let things find the center. Remove the transmission and tighten the clutch screws down the rest of the way. You should be good to go.

Kurt in S.A.

[BubbaZanetti]

I think you can get around needing an alignment tool...at least I did on my /2 and it should be essentially the same. Before you tighten down the screws that hold the clutch pack together, slip on the transmission enough to engage the clutch splines...even with the longer bolts in some of the screw holes. Then actuate the clutch and let things find the center. Remove the transmission and tighten the clutch screws down the rest of the way. You should be good to go.

Kurt in S.A.



i've never taken apart an airhead clutch but i've removed a transmission from one and the clutch looks very similar to the one on my oilhead. all i did to "make" a centering too was remove the pushrod from the tranny, find the exact size socket that would fit over the pushrod and through the clutch splines without allowing any free play and centered it using that. 17mm crafstman 3/8 drive if i remember correctly (this was on an oilhead clutch)

same goes for "balancing" the unit. just mark everything clearly with white out then realign.

[PeoriaMac]

Go ahead and replace it. Saves time, lets you know what things look like inside. Won't take that long. I bought the "BMW Centering Tool" from Ed Korn. Cheap insurance, and gives me something to lend out at tech parties.
Make sure you return the flywheel to the place in relations to the carrier.
Don't ask me how I know.....

[Motor31]

Make sure you return the flywheel to the place in relations to the carrier.
Don't ask me how I know.....

OK How do you know???????????



:bolt

[RandyB]

ABC has a series of good tech articles on GS maintenance. Lot of stuff on clutch and spline work.

www.airheads.org

[davidswanson]

My 1991 GS-PD has approx 44k miles I ride it loaded & two up frequently. For example, last July 7k miles on a trip to Alaska's Artic Circle. I went through the service records provided me when i purchased the bike and the clutch has not been replaced recently. So I am going to tear into it. Thanks for all your comments

swanny

[PHMarvin]

Hi, Swanny,
With only 44k on the clutch, my guess is it's fine and needs nothing. That said, since the gearbox is already off and the clutch is out in the open, were it mine, I would at least take it apart and inspect it. I might not change it, but at least I could see how much (or how little) it is worn.

[PGlaves]

Clutch removal and replacement involves two issues: balance, and centering of the clutch disk.

Balance: Conspiuously mark the three bolted pieces; the flywheel/ring gear, the clutch cover and the pressure plate. I use red or yellow paint to put a dot where all 3 will line up. If I then like what I find I can replace everything as found.

BMW marks each piece with either the heaviest or lightest point - I forget which. In either case, properly assembly is to locate the factory paint marks as close to 120 degrees apart as you can - spreading out those light or heavy points around the circumference. If you do this the entire assembly will be in balance within tolerance. If you don't you can get a wicked vibration at certain RPM. The trick here is finding the faint white paint mark (often about the size of a thumbprint) on the flywheel which you are not replacing. That's one reason I mark everything before I take it apart. That way if I find the paint on one of the other two pieces I have a starting point to look for the paint on the flywheel.

Alignment of the clutch disk with a centering tool is helpful to make the transmission slide in silky smooth. There are work-arounds if you don't have a centering tool. I often use the clutch rod slipped through the center of a socket where the outside circumference of the socket matches the inside of the clutch hub. This - with a visual check works just fine.