A new noise. Speed-dependent clickity click

[Sideshow_S]

So if I get rolling in any gear and pull in the clutch lever to coast at speed, I get a clicking. Not a high-pitched click like a playing hard hitting spokes, but like the lower sound that a large hex bolt would make rolling around in a cast bowl.

As it's speed-dependent, it seems like it would make sense that would be on the clutch or afterwards in the drivetrain. Could the rivets that hold in the clutch material just be shot and so the material is clattering around? The sound does seem to be coming from the transmission area, but has that hollow sound of possibly being in the bellhousing or the hollow swingarm. I can feel a slight vibration in the throttle that accompanies the click.

Lately, as I pull the clutch in at neutral with the bike running, I get more clatters than I used to.

The bike shifts fine and the clutch isn't slipping at all. It hooks up the same as it used to, but there is a slight jerk that seems to have grown, which I used to attribute to the slack in the fuel line. Could that be the clutch slipping and catching? With 93K and the stock clutch, I wouldn't be surprised, but I would have expected the clutch to start slipping before this happening.

Anyone got a clue on this? Is there a bolt that may have come loose that is working it's way out and clicking on the housing as the drivetrain turns? I know I can just dive into it, but I was really planning on doing other things this weekend.


Man, I was so planning on getting down to Arkansas, too.

[RBMann]

With 93K on the stock clutch I would say it is toast one way or the other. If the click is speed dependent and shifting gears does not change it then maybe it is a u-joint.

RB

[wswartzwel]

If I remember right you have some good friends with a truck... That came to Arkansas to haul you home before. So what if it is making noise....

Falling leaf Rally is next weekend...

[R111S]

Turn the Rear Wheel with the engine off and the Clutch lever pulled in...try it in neutral, 1st, 2nd, etc. My Airhead Transmission made a noise that sounds similar to your description when the output shaft bearing went bad (3 different times before I decided to stop popping wheelies)...doing the above test always let me know when it was gone.

[Sideshow_S]

RB, have you totalled a clutch before? You doubt the lifespan -- I'm curious to push it!

Dan, thanks for the insight. You sparked my motivation to get on top of things tonight.

Bill, I was sort of thinking the same thing -- 'cept I didn't want to show up at Potosi and be asking people if they had any parts available. Getting all the way to where I want to ride and having the bike break down or some animal go suicidal gets old after the first two times.

So . . . tonight's effort revealed the problem. I'll get typing.

[Sideshow_S]

Dan's thoughts made me leary. I didn't want to dive deep into the S without a proper shop, lift, stand, or anything else. But if I'm going to head out to the Falling Leaf Rally, I'd at least like to know what my odds are of a complete round trip.

March: Swapped pivot bearings, misaligned the u-joints upon reassembly
June: Realigned the shaft. Vibration reduction was good, but over the summer, worsened.
September: Clutch-noise issue that started this thread.

So I dropped the final drive tonight. The inboard pivot pin gave me clue#1. It had a circular cut to it at an acute angle, as if the driveshaft were milling it away. The outboard pin was in good shape. Pivot bearings intact and tight -- no crushed needle bearings, etc. that could cause the vibration.

Small metal shavings from the pin were strewn about the housing, some mixed with oil from the leaking input seal on the final drive. The boot leaked a good 10cc's of gear oil. Mmmmmmm. . .

The rear driveshaft u-joint, which had milled away a portion of the pivot pin appeared solid and amazingly undamaged. Minus, of course, the very faint appearance of the interference which had been happening. I was wondering where the slop was that was allowing this play that caused metal-to-metal contact.

I pulled the intermediate splined shaft out. Things looked good. Male and femal splines were good. Then I pulled the intermediate shaft off of the final drive's shaft.

That's when it all became clear.

When I realigned the driveshaft after misaligning it the first time, I didn't check the intermediate shaft's female spline at the time. I'm guessing the problem had already begun to propagate from the excess vibration involved in riding the bike for a month with misalignment and negligant (honestly purely lazy) attention to the need to fix the misalignment.

So I didn't catch the fact that 3 months ago that these splines were already damaged and continuing to ride on them were only making them worse.






They got so bad that there was slop in the drivetrain. The clattering was the splined shafts knocking back and forth as the wheel turned going down the road. Without a load on the drivetrain to make it accelerate or decelerate, the driveshaft was getting knocked forward via the inertia of the wheel, slowing, then getting knocked, slowing, and getting knocked. This was the clattering noise I was hearing.

The good news: Final Drive spline is solid and undamaged, despite the ugliness of the contacting female spline. I have spares and the bike has been tested and is smoother than it was since 70K. I pull in the clutch and there's no noise to be heard! I'll be at Falling leaf!

[RBMann]

Sideshow_S

Was that rear u-joint completely engaged on the FD shaft? The wear does not look that deep on the u-joint.

The first clutch, brother-in-law's bike, was slipping because the trans. fluid had leaked onto it. At 60K miles it was worn 60% of the difference between the wear limit and a new clutch disc. so I assumed 100K would be it for that bike's clutch. The bike had a lot of highway miles and was not abused. At 60K clutch #2 was my bike. The disc was not at the wear limit but was worn in a pear shape with the metal bits showing heat checking. Inner dia. of the disc had about 50% wear and the outer edge about 80% wear. Same number of easy highway miles as the first bike but a fair number of burn-outs. Abused? Probable yes. I went in to look because it had the oil leak stains between the engine and trans., it was not feeling that solid anymore and I was planning to ship the bike oversea for a trip.

Glad you found your problem but I still believe you will also be doing a clutch soon. My understanding is, as they get toward the end of their live there is slippage before you hit the wear limit. Plus they shift better and the clutch feels smoother with the new pieces and the input shaft lubed.

Good luck, RB

[R111S]

Hey Side_Show we didn't see you at FL2008? Hope all is well.