Clutch plate question

[lutorm]

I finally took my clutch apart to see why it was so heavy, and, sure enough, there were 4 springs in there...

But I have another question: The outermost friction plate was not mounted in the same slot as all the others. See picture at http://blog.familjenjonsson.org/blog/20 ... igation-1/. The pictures in my Haynes don't even have that second, shallow, slot. Has anyone seen this before? I'm pretty sure it's not supposed to be mounted like that.

Thanks,

/Patrik

[Cammo]

Wow that is certainly fubar'd!



I imagine there was some sort of clutch issue which the previous owner may have attributed to plates snagging on the fingers, and also fitted an extra spring to help it out?

If the wrong plates were used (or rvf plates) the clutch won't bite properly, good info here: http://www.akhara.com/nc30/nc30clutch.html

At least you've found the cause and it can be put right.

[lutorm]

Hey, thanks for that link. I'll definitely measure the stack before putting it back.

The clutch basket is in pretty good shape. There are definitely little marks where the friction plates hold on, but they don't seem sharp enough that they would cause the plates to snag. I'll chalk it up to general incompetence -- there's been so many other things not put together right with this bike...

[lutorm]

Well, motherf...

The friction plates are all between 2.9 and 3.0mm, so I think those are correct and just worn. (Haynes says service limit is 2.8mm.) The metal plates, though, are all 1.9mm. So it seems those are actually for an NC35. And sure enough, when I put the assembly together with the 3 springs it should have, the clutch slips like nothing else. Like unrideable. The height of the spring assembly, btw, was 5.7mm. This is curious because the Haynes claims the standard height is 5.3mm. How do you make the springs higher?

I would have guessed that if the plates are too thick, the clutch would be heavy instead of slip. But who knows.

So I guess I need to get the right metal plates... I wish I could have a word with whoever worked on this bike before!

[Neosophist]

I wish I could have a word with whoever worked on this bike before!

To be fair you will probably be sympathetic with them after you find out the reason.

The problem is your clutch is worn, those little ridges will make the plates snag a little and give you that hard to find neutral issue sooner or later if you dont have it now.

Race bikes cost money to keep racing, the clutch costs a LOT of money to rebuild properly.

10 new friction plates, 9 new steels and 3 springs.

To avoid issues your best replacing everything in your case.

I'm actually doing exactly the same too, ordered up some Honda plates yesterday

Metal plates are about 7 quid each and you need 9.
Friction plates are about the same and you need 10.

Springs are dictontiniued so I dont know about those, perhaps EBC or sometbody makes some. If yours have gone soft they need replacing.

So for many people the cost of a couple of hundred quid to overhaul a worn clutch on an old bike is quite a bit of money so they often bodge.

A heavier clutch for the price of one old spring is cheaper than replacing everything.

[lutorm]

I wish I could have a word with whoever worked on this bike before!

To be fair you will probably be sympathetic with them after you find out the reason.

Heh, maybe... I ordered new plates (both types). I guess I'll try to even out the ridges in the basket before mounting them. The height of the springs is fine, so unless they've softened without flattening, it seems they should be fine.

And it does drag a bit, which makes it hard to find neutral. However, it only does it when warm...

And just to be clear, I'm not racing the bike. I just want it for street riding.

[lutorm]

Mostly happy ending on this story. I fitted new plates with the correct thickness for the NC30. The old stack had the thicker NC35 plates and I now realized it only had 9 friction plates, presumably because with the thicker metal plates the full stack wouldn't fit. The new thickness came out to 45mm for the complete set of plates, compared to 43mm for the old one. Presumably this was why the clutch was slipping so bad before. Now it seems to work fine. I only did a short test ride, but there was no slipping and it didn't seem to drag when warm like it used to either. The clutch cable adjustment is much more reasonable, too.

The only problem was that when I took it apart I noticed that the inner thrust washer is missing. Since it's obviously worked fine without it for God knows how long, I put it back together anyway so I could test it. I guess I should order a new one, though.