Clutch warble at take off?

[Hoomgar]

On my Blue 78 GS1000 the clutch will warble (don?t know how else to explain it) at take off if you take off a little hard. If I let the clutch out from a dead stop nice and easy and take off like I?m riding a tour bike then there is no issue.

But if I try to take off faster, and I don?t mean slamming it, I mean just a little harder and faster then there is a vibration and a wobbling warbling of the clutch until it fully engages. Once engaged and once moving there seems to be no issue. And the clutch does not slip.

What do you make of it? Warn splines on the clutch basket? Maybe the clutch plates have warn groves in the basket? What could cause this? I guess I better open it :|

 

[Jethro]

I guess I better open it

Yep, I'd say some surgery is a good idea. I imagine that could be warped clutch plates? Just guessing...

 

[Hoomgar]

Ahh! Didn't think of that :-k

How can I tell? Will the warping be visable? Or maybe lay them on a known flat surface to check? I guess I will open it up because I have the oil drained and pan off right now anyway due to other repairs so I'll crack it open and pull it out. I can measure the plates with my caliper while I'm in there anyway then.

I know the baskets are notorious for wearing on these. Where is the cheapest place to get a new basket if it comes to that?

 

[Jethro]

Yeah, lay 'em down on a piece of glass or something. Check both the friction and steel plates for tolerance.

Don't know where to find a good basket, but if I was replacing mine, I might look at a billet unit, but lots of $$$$

 

[Hoomgar]

OK clutch is out. The plates look good. Both friction and steel separators as well. They are not warped and mic to the right thickness for the tolerances listed in the factory service manual.

My suspicion of the clutch basket made me look at it harder. (I had the same issue with my other 78 1k) and I think it is it. But what I am not sure of is there any amount of play that is considered normal in the clutch basket or should it be rock solid?

Mine has some play. I took a quick video clip of it so you can see it. I think the clip is good enough that if you look you will see the basket moving in and out as I pull and push on it as well as hear it. No worries. I smashed this clip down small enough that it is good for even the slowest of dial up connections. It is only 72k. Smaller than some pictures.

Please look at this and tell me what you think?

http://home.ptd.net/~megabyte/misc/Basket.wmv

 

[Anonymous]

It's hard to remember, but I think, where you are, a slight amount of slack is normal. While you have it this far apart, take the basket out so you can inspect the springs, rivets, & backing plate, that's usually where the trouble is. Don't lose the little rubber plug that goes where the oil pump drive gears go, it just sits in there & can fall out.

 

[Hoomgar]

Will do Ron, thx

So you think that amount of play is normal? It is straight in and out. In other words you can't wiggle it left and right. It is sliding straight in and out on the splines.

 

[Anonymous]

It's been a long time since I had one apart, but I think a small amount of play is expected, not 1/4'' or anything like that, but enough you can feel & hear it.

 

[Hoomgar]

I was told to pull it for sure since I had that open and look at the rivits. I did and there is some play left to right but isn't that what the springs are in there for? There was no noticable separation pulling and pushing the back plate and the basket apart from each other.

So I buttoned it all back up and we will see. I made sure to torque things down correctly. Maybe that was the issue? I did notice that the clutch spring screws were not consistant. Some were really easy to turn out and others were tight.

Another thing though was the hub for lack of a better name but the other part that the screws and springs go into to button it up. That has some very noticable wobble in every direction even after being sloted completely onto the splines. Could this be it or is that normal? I would think that should fit snug and not wobbly?

We'll see how this does when I get it running again.

 

[Jethro]

Yeah, I'd say the amount of play is normal. Some is to be expected. Don't know what to tell you! (I'm a big help...)

 

[lhanscom]

Just a thought, have you checked the run out on the hub itself? Maybe somethings warped a bit?

 

[vstan905]

Possibly weak springs?

 

[Hoomgar]

Luke, what do you mean?

vstan, I thought about that. It was an after thought. I had already buttoned it back up. I should have checked them when I had it open.

Well I did get to go for a burn tonight and the clutch seems all good and well now. It may have been that the hub nut was loose. It wasn't very tight at all when I went to take it off. I broke it loose with no tool to lock the hub and basket together and the bike on it's center stand. We simply put it in gear and my son held the rear brake down with his foot. It poped right off with almost no force at all. It was loose! I really think that was it. Time will tell though. I need to ride it more to be sure.

 

[lhanscom]

Well I did get to go for a burn tonight and the clutch seems all good and well now. It may have been that the hub nut was loose. It wasn't very tight at all when I went to take it off. I broke it loose with no tool to lock the hub and basket together and the bike on it's center stand. We simply put it in gear and my son held the rear brake down with his foot. It poped right off with almost no force at all. It was loose! I really think that was it. Time will tell though. I need to ride it more to be sure.

That would definitely cause the problem you were referring to. Glad you got her fixed up!