Occasional clunk noise when letting out clutch in 1st gear?
 

Hey all,

What seems to be the clutch/gearbox on my XT600 recently started making the occasional clunk sound when I'm in first gear with the clutch lever pulled in and start letting it out. It isn't accompanied by any judderiness but the noise is a bit disconcerting.

Any ideas on what could be the cause of this? The bike had some stuff done to it a day before I started noticing it happening:

- changed the exhaust
- changed the clutch and brake levers
- had the rear wheel and tyre changed (double checked the chain slack and it looks to be within the specs in the manual)
- drilled out a stripped allen bolt holding the tacho cable in the tacho drive while it was still attached to the engine

Likeliest culprit seems to be either the rear wheel change or the bad vibrations from drilling out the allen bolt borking something up.

Here's a short video to illustrate:

https://sendvid.com/e64v507i


Thanks!

I had a mechanic change the wheel and tyre and I'm hoping they would've checked for that sort of thing before fitting it.

Here's a video of me checking the play in the cush drive. Is this kind of play normal?

https://sendvid.com/4kvve0l3

Sounds like cush drive rubbers may need packing with some rubber (can use some old inner tube rubber)

Also check that the chain doesn't have a tight spot when you rotate the wheel. The mechanic may have adjusted the chain in a slack area rather than the tight spot so could be too tight?

Thanks for all the help!

It looks like it was the cush drive rubbers after all. I took it back to the mechanic that fitted the wheel and they confirmed that the cush drive rubbers are worn. Apparently the rear sprocket should only have 1-2 millimetres of play instead of the 7mm or so of play in the video. Would've assumed mechanics usually check for that sort of thing when fitting a new wheel. Also, I came across this example of a worn cush drive on a DL1000 and my bike has the same level of play:

https://www.youtube.com/watch?v=D03gRtDqZYs

I ordered some new cush drive rubbers so hopefully the problem with be resolved when they're fitted.

Is there a certain trick to adjusting the tightness of the chain on an XT? It has these notched adjustment plates on either side which aren't precise at all: one notch to the left and there's 25mm of slack at the tightest point, one notch to the right and there's 45mm, so it seems impossible to set it between 30-40mm as Yamaha recommends. 25mm was way too tight (bike struggled to shift into second), 45mm felt okay, and the first gear clunk happened regardless. Didn't have the clunk with the old wheel so the chain itself seems healthy.

Welp, I had the new cush drive rubbers put in and there's far less play in the rear sprocket, but the problem remains.

Any more ideas?

With a dead motor, can you roll the bike fwd freely when pulling the clutch (in gear)?


if not clutch is not separating as it should, could be wrapped plates, grooves in the clutch hub or basket fingers, clutch hub nut not tight, etc.



do the test first....

I've got it at 2mm at the gap which translates to about 1cm at the end of the lever. The chain is tight on the rear sprocket and doesn't pull away.

I know it's normal to clunk while going into first gear, but the clunking while slipping the clutch in first gear is what I find strange.

Yep, the bike rolls forward freely in gear with the engine off and clutch pulled in.

What I did notice is that if I move the bike back and forth, there's a quieter clunk which seems to be coming from the gearbox or clutch. Is this sort of thing normal?

Video to illustrate:

https://sendvid.com/87uug5xi

now that i managed to see your first video, is the plastic chain slider over and under the swingarm pivot intact? to me it sounds now like the chain hitting the swingarm metal.


part 14 here


https://www.cmsnl.com/yamaha-xt600e-...l#.XSTryFZS9zk



youd be hearing that too when pushing back and forth.

I'd get the bike up on a stand so the rear wheel is off the ground. Might be easier to see where the sound is coming from. You might also get the chain from the front sprocket and turn the front sprocket manually to see if you can get the sound. That way you can narrow it down / whether it's rear wheel/chain related or clutch/outputshaft/gearbox related

Checked it out and the chain slider is intact.



Good idea, now I just need to get some sort of stand!