Thursday, January 24, 2008

Clutch Rattle

With the covers off, I had access to the clutch. I removed the springs, spring bolts and plates and found the source of my noise - a loose clutch nut. The reason for the loose nut was very clear - the stock setup uses a large lock washer under the nut that is then bent up to lock it in place. The problem with this is that the lock washer is made from soft steel so that it can be bent up. The initial torque of the big nut plus the constant shock of power transfer through the clutch eventually crushes the soft washer until it releases the tension in the tightened shaft. It's a common problem with this kind of arrangement.

After a while of floating free, the shaft splines beat up the aluminum splines in the clutch hub and it gets even more loose. The ultimate solution is getting rid of the lock washer and using a billet clutch nut with red loctite and a brand new clutch hub. I don't have a billet clutch nut or new hub, but I do have red locktite which will hopefully solve the problem. There are available, but I'll see if this works first. It's easy enough to get at the clutch by putting the bike over on it's sidestand, so I'm not too concerned about re-doing it.

I gave the steels and fiber plates a quick measurement to make sure they are OK, and they're within specs. I thought I felt a little clutch slip on one of my rides, so the springs might be getting weak - I'll change them later if it returns. The springs in the clutch were loose and rattly, but just tightening down the hub should cure the worst of the noise.

I knocked the new seal and sight glass into my freshly-polished clutch cover and got ready to bolt it on with new allen bolts. I also changed the oil yet again, and replaced the oil filter and it's o-ring.

Looking good!

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