Clutch pressure plate has two positions

[ejdirin]

I was having some issues with my clutch sticking. I took everything apart and cleaned the plates and replaced the thrust bearing and springs. Things were working ok when it was dry. However, whenever I'd pop the bike into gear and rock, and then try to disengage, the clutch would stick again. It would loosen up after a few rocks.

We were trying to see if the position of the pressure plate made a difference and discovered that the pressure plate had two positions; one flush with the last friction plate, and one some distance from it (about one plate distance). Does anybody know why this is? I'm trying to tune the clutch so it doesn't stick. When we put the pressure plate in the later position, the clutch won't even engage. We haven't tried this with oil in it, however.

Anybody have any guidance for us?

If this isn't a feature of Yamaha pressure plates, could the actual plate be warped? When we'd roll the bike with the plate on, it seemed to roll unevenly. And this was reproduced with all the friction and clutch plated removed. What could be the reason for that? The clutch boss didn't seem to be off-balance.

 

[ejdirin]

The more I think about it, the more I think the pressure plate is warped or bent. First off, it rocks very slightly when I lie it on glass. Second, the plate has 6 potential positions. The "out" positions would be 1, 2, and 3. The "in" would be 4, 5, and 6. This doesn't make sense to me. If Yamaha wanted to make the pressure plate adjustable, I'm sure they'd go stepwise from 1 to 6 (which might not be a bad idea to make up for friction plate swelling, etc).

Also, using this pic (courtesy of inxs), there is only one way to mount the plate. In my situation, that would be an "in" postion, in which the plates stick. Its possible that the clutch and friction plates could be shot, but that doesn't account for the uneven rotation of the pressure plate.

So, unless anybody has any other thoughts, it looks like I might need a new pressure plate, which brings up a whole new set of problems bc I don't know where to get one. Any ideas?

Also, while we're on ideas of where to get things, I'm missing a jet needle preload spring for my BS38's. Mikes only sells BS34 springs.

If anybody has any recommendations for either, I'd appreciate it. It sucks when you think things through and the only logical explanation is that your equipment is faulty....

 

[pyrocentric]

You can double check your assembly here:http://www.biker.net/650parts_index.html

If it is warped though, I guess you could try ebay.

Are you sure you've got those clutch bolts tightened evenly? I use a torque wrench and phillips bit socket.

 

[Sundie]

Also, while we're on ideas of where to get things, I'm missing a jet needle preload spring for my BS38's. Mikes only sells BS34 springs.

They're interchangeable, just go in in a different order. They're not a specific tension or anything. Just replace them in pairs. If you're talking about these, that is.

 

[Travis]

Your explanation of the 6 positions of the clutch was very confusing to me until I read it about 3 times to understand what you meant. The pressure plate only goes on one way. You line up the hole in the plate and the dimple in the hub. All the other 5 ways are wrong. They are not designed to allow for expansion of the frictions plates.. the adjustment in the worm gear will take care of that if it's a problem. The pressure plate should be pressed against the last plate when you tighten all the screws. When you pull your clutch lever, the plate should move out evenly (about 2-3mm) to take pressure off the plates and allow them to slip between each other. When you put the plate on wrong, your clutch will not engage because the pressure plate is not doing its job (applying pressure to the friction and steel plates).

You need to check to make sure that your worm gear is adjusted properly and that when you pull the clutch lever, the pressure plate is moving out enough to allow the discs to slip between each other, and that it's moving out evenly. If it doesn't move out far enough, then you need to make sure that everything on the left side of the bike related to the clutch is working properly (worm gear housing could be cracked, push rod, clutch lever, cable) and if the plate moves out far enough and evenly, then you have a problem with the clutch itself. If the plate moves out, but not evenly, check the springs again or make sure one isn't broken. If your pressure plate is warped, you probably need to replace that first.. I'm not sure how that got warped in the first place unless putting it on in the wrong position and tightening the screws would be enough to warp it.

Take a look at this http://www.xs650.com/forum/showthread.php?t=143 especially post 6 and 7 talking about adjustment and assembly and see if you can't figure out what the problem is.