Strange clutch problem

Jim Stewart js at strappe.com
Wed Jul 1 13:01:41 PDT 2009


Hi, guys -

Last summer on a 3 day ride we had an odd problem first thing in the morning of 
the second day.

Ravi's SV 650 had a stuck clutch, just like a British bike. I've never seen this 
before in a Japanese bike. After starting it in neutral and pulling in the 
clutch, it wouldn't disengage. Just like my BSA. It had just been sitting overnight.

I tried to break it loose by pulling in the clutch in second gear and cranking 
the starter, but no good - the starter just pushed the bike across the parking 
lot. Finally I started the engine in neutral, pulled in the clutch, gritted my 
teeth and jammed the shift lever into first. Just like I have to do to my BSA.

It worked, and the clutch behaved normally thereafter. No problem the next 
morning, no problem since then.

I want to emphasize that this wasn't a cable or linkage problem - the clutch 
felt normal when I pulled on the lever. But the plates were stuck together even 
though the spring pressure was removed.

In a few days the bike's coming out to my place for a clutch inspection, but I'm 
not inclined to replace the friction plates in a working clutch on a low-mileage 
bike. Unless, of course, we find something wrong.

Anyone else had this problem on an SV? Or any other modern bike?

Suggestions welcome!

------------------


Here's my response to Ravi:


 > Ravi wrote:
 >> what exactly do you want me to buy?
 >> Also, where should I buy it from that you recommend?
 >>

I wrote:
 >
 > That's a tough question.
 >
 > Am I correct that your clutch had never stuck before, and that it hasn't
 > since?
 >
 > A sticking clutch that has to be broken loose with a shock is common on
 > Brit bikes, and it's caused by a poor choice of friction material in the
 > clutch plates or a poor choice of oil. Or both. But with a Brit bike the
 > problem would typically occur after the bike had been sitting for a
 > while, several days or more. Not overnight, as in your case. And it
 > wouldn't go away after one episode.
 >
 > Furthermore, I've never heard of this problem with any Japanese bike,
 > old or new.
 >
 > Since the clutch operates in oil, sticking can be caused by either the
 > friction plates or the oil - do you recall what brand/weight oil you
 > were running last summer? In the absence of any other data, I'm inclined
 > to think the problem was oil related.
 >
 > Beth mentioned notched splines in the clutch basket, a problem she has
 > on her SV, but that wouldn't cause your problem - notches cause the
 > clutch to grab suddenly when engaging, but don't cause problems
 > disengaging.
 >
 > My inclination is to inspect the clutch first - in which case all we'll
 > need is a new O-ring for the clutch cover. But if you want we could
 > replace the friction plates anyway. It won't take any longer, since
 > we'll already have them out, but it'd be a stab in the dark at an extra
 > $110 or so.
 >
 > I recommend Ron Ayers: http://fiche.ronayers.com/ Check out the clutch
 > fiche for your bike: http://tinyurl.com/m2d66t
 >
 > Note that the drawing is incorrect - it shows a total of 8 friction
 > plates (the ones with the tabs on the outer edge), 7 is the correct
 > count. There are 6 of 21441-37440 @ 13.28 each and one of 21440-19F00 @
 > $31.24. The steel plates between them don't wear - with extreme abuse
 > they will warp, causing drag on disengagement (not your problem).
 >
 > You will need the large O-ring for the cover, 11484-19F01, $11.18.
 > http://tinyurl.com/l7h5df
 > It's *possible* that the dealer would have this in stock. If they stock
 > anything at all anymore.
 >
 > ----------------
 >
 > This would be the appropriate time to change your oil, since we'll need
 > to drain it to work on the clutch. Unless you've just done that, in
 > which case we can put it back. Or work on the clutch with the bike on
 > the sidestand.
 >
 >
 > -js
 >




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