Clunk when letting clutch out

devauxb · May 9, 2014

Every time I let the clutch out to engage, I get a decided 'clunking' sound as the clutch engages. Even when I let the clutch out slowly, at the time of engagement, it consistently makes the sound. It has been doing it for a long time, doesn't seem to be getting worse or affect the drive-ability. It is kind of hard to tell exactly where it is coming from, although somewhere between and including the transmission to final drive.

Clutch and driveshaft splines were inspected (everything was OK) and lubed at about 44K miles, bike now has about 56K miles. I think that the sound started up shortly after the spline lubes. Any ideas? Something to be concerned about?

bikerfish1100 · May 9, 2014

first BMW?

dieselyoda · May 9, 2014

Bike not running, off the center stand, rock forward and reverse. You should get close to where the noise is coming from. My gut feeling is a u-joint.

pauls1150 · May 9, 2014

Agreed, "clunk" points to a U-joint.
Wonder if the shaft was phased properly at re-assembly...?

dieselyoda · May 10, 2014

Pauls1150 said:
Agreed, "clunk" points to a U-joint.
Wonder if the shaft was phased properly at re-assembly...?
View attachment 44878

Not to be a PIA but u-joints out of phase is first noticed as a weird vibration on acceleration. Out of phase will cause a very rapid deterioration of the trunnions and cause a clunk.

I thought of something else, I do that sometimes, a brake caliper hanging up in the rear and suddenly letting go could be perceived as a clunk.

pauls1150 · May 10, 2014

Again, Agreed; I was thinking that perhaps the shaft was phased correctly before the service, and if the tech wasn't careful there, he may have exacerbated what used to be "only very slightly worn" joints to become an issue.

globalrider · May 11, 2014

devauxb said:
Even when I let the clutch out slowly, at the time of engagement, it consistently makes the sound.

Have a second person with a mechanic's stethoscope listen to the various components as you engage the clutch and drive off at a walking pace.

When you pin-point the area, you can make a better diagnosis.

devauxb · May 12, 2014

Thanks for the suggestions. I rocked the bike back in forth in 1st gear with engine off. I do hear some slight mechanical noise in the driveshaft. Should I not hear anything or is some level of noise expected?

I can make the clunking go away if when sitting on the bike, clutch in, I rock it back slighly. Then when I do let the clutch out, the noise is not present.

So, it seems to be coming from the driveshaft somewhere. Sounds like I will need to have this looked at. Is it possible that the driveshaft was not put back in correctly (as it occurred once the spline lube was done)? From what I read it needs to be 'snapped' in. Or is it more likely the universals?

globalrider · May 12, 2014

devauxb said:
I do hear some slight mechanical noise in the driveshaft.

As long as you don't confuse it with the slight noise in the final drive gears which is normal.

pglaves · May 12, 2014

You should not hear any noise from the driveshaft. The splines should be tight enough and greased so as to make no sound. The universal joints should be silent too.

happy wanderer · May 12, 2014

You might want to get out your smart phone and take a short video of this noise with the bike on the center stand. Upload it to photo bucket or picassa or whereever and post a link to it here. Let the guys have a listen to it. I'm not familiar with the 1150 RS but both oilheads I've owned had a bit of a clunk in them as you describe and this was just built in drive train play. Nothing wrong at all... or as we love to say here "They all do that" ?

bikerfish1100 · May 12, 2014

happy wanderer said:
You might want to get out your smart phone and take a short video of this noise with the bike on the center stand. Upload it to photo bucket or picassa or whereever and post a link to it here. Let the guys have a listen to it. I'm not familiar with the 1150 RS but both oilheads I've owned had a bit of a clunk in them as you describe and this was just built in drive train play. Nothing wrong at all... or as we love to say here "They all do that" ?

hence my initial question, which was never answered.

dieselyoda · May 12, 2014

bikerfish1100 said:
first BMW?

I'm not sure how that matters. I own an Oilhead, a Brick, a Bricklet and have owned a bunch of Airheads in the past. I have a Wedge and a Hexhead in my shop right now. None of them "clunk". My old KZ clunks and it has chain drive and a huge rubber damper. It clunks because I keep forgetting to adjust and oil the SALT chain.

Maybe we aren't talking about a "clunk" per se as I see my bikes have some considerable "wind-up" to the drive line. A video would be most helpful but my gut feeling is still with a u-joint.

Don't forget, loose bolts on the rear wheel, loose frame to engine/tranny mounts even a loose center stand might give you some "clunks".

I still have no idea why my center stand bolts on my Oilhead come loose every 5K kilometers or so. And no, I don't use red Loctite, it's not allowed in my shop.

bikerfish1100 · May 13, 2014

for someone unfamiliar with the dry clutch characteristics of an Oilhead, a clunk can be easily produced when disengaging the clutch, with nothing being wrong with the bike.

you know... "they all do that".

just another line of thought is all.

Clunk when letting clutch out

devauxb

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bikerfish1100

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dieselyoda

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pauls1150

MOA #24991, south of Los Angeles

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globalrider

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devauxb

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