1975 Clutch Plate Thickness

YamadudeXS650C

Central New York XS650
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Inspection of the clutch parts in my '75 purchased last year revealed plates that are 3.00 mm in thickness. My Haynes manual says the wear limit is 3.10mm and new they should be 3.5, so I ordered 7 of the 39-1133 plates (apparently correct for the '75) from Mike's, which mic at 3.00.

Damn, I should have looked this one up here at this forum, before ordering. From what I am reading in previous posts, my '75 does in fact take 3.00 plates, am I correct? Which early years used the 3.5's ?

Thanks !
 
Yes, your clutch uses 3mm thick plates. The '70-'73 clutches used the 3.5mm plates. As you've discovered, the Haynes manual is wrong. I think the Clymer is too. Most of us prefer using a factory manual, with maybe a Haynes or Clymer around for cross-referencing stuff.
 
Thanks 5Twins.
Interesting that there is no wear on my plates. The side cover gasket seemed to have been in place since '75.
Oh well, a fresh set of plates will likely make for a slightly better-functioning clutch.
 
I rarely find them worn either. I think the stock plates are very robust. I've never tried any aftermarket ones but have never had the need to. I have quite a stack of still good originals from parts bikes and used clutches I bought.
 
Hi 'dude,
betcha you're not alone.
I wonder how many owners of '74 and newer XS650s bought new clutch plates that were no thicker than their old clutch plates because Haynes or Clymer didn't mention that the newer models had thinner clutch plates?
And how many of those people simply stashed those plates away unused because they didn't want to pay to return them?
 
Hi 'dude,
betcha you're not alone.
I wonder how many owners of '74 and newer XS650s bought new clutch plates that were no thicker than their old clutch plates because Haynes or Clymer didn't mention that the newer models had thinner clutch plates?
And how many of those people simply stashed those plates away unused because they didn't want to pay to return them?

I am chuckling (painfully) to your comments, Fred, because I am about to create a "good used clutch plate stash." :D

However, I can say this: I finally replaced the unworn plates in my '76 two years ago after doing EVERYTHING else indicated at this site to cure the "sticky plate syndrome", that is, the inability to free the clutch with the kicker prior to starting. The new plates were the instant cure. No amount of cleaning them fixed the stickiness issue. Therefore, the new plates on the '75 will be some insurance against that annoying issue.
 
When a young broke dirt bike rider I'd re-arrange my clutch plates thinking that would improve the wear pattern happening. And I think it did. Now I have a slow dripping XS side cover and will get to it. I'm tempted to restack my clutch plates . Any reason not to ? thx, -RT
 
When a young broke dirt bike rider I'd re-arrange my clutch plates thinking that would improve the wear pattern happening. And I think it did. Now I have a slow dripping XS side cover and will get to it. I'm tempted to restack my clutch plates . Any reason not to ? thx, -RT

I can't imagine that it would make much difference, unless some individual plates are wearing unequally for some extraordinary reason. In that case, I would replace the uneven ones.

However, I would pay attention to the lengths of the springs, measuring them with your micrometer, then distributing them around the circle in a pattern that best equalizes the pressures they provide to the clutch pack.

BTW, I recommend, as others have, that you use copper washers on the 4 side cover bolts that are under the oil bath. And use a high quality gasket (eg Athena) coated with grease on both sides.
 
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Good tips Yamadude on the springs.. I buy as much Yamaha maintenenance parts as there is avaliable. The local Yamaha shop is a great place to visit.. thx, -RT
 
You might want to inspect the orientation of the steel plates. They are stamped out which makes the edge on one side of the teeth sharp, the other side rounded. Most of us stack them in there with the rounded edge facing out. The theory here is that the plates will separate easier when you pull the clutch lever in. They're not being pushed apart, they just "float" apart, so doing it against a rounded edge rather than a sharp one just seems to make more sense. You have 6 springs pressing them together again so that should easily overcome any drag the inward facing sharp edges create. But, you can also help that by knocking those sharp edges off. Some mention filing them but, my God, there must be several hundred little teeth there. I'm dedicated but not that dedicated, lol. The simple solution is to wire wheel them. It knocks the sharp edges off in just a few minutes. Do still face that side in. It's still not going to be as rounded as the other side.
 
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