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'11 STR - Clutch slippage and no more adjustment

3K views 24 replies 5 participants last post by  jamesymurray 
#1 ·
Hello all,

Adjusting free-play on my clutch has become almost a weekly occurrence.

After a week or two the clutch starts to slip a bit in higher gears at higher revs, so I adjust free-play at the lever end.
About once a month, I then have to adjust at the clutch end after running out of adjustment at the lever.

Inevitably, I have now completely run out of adjustment at the clutch end too.

Is it normal to have to go through this much adjusting (I do around 120 miles a week), or is there something up with my clutch?

I was planning to book it in for a service next month, although I'm thinking I might have to bring that forward to get this clutch sorted.

Or is it something that can be done at home?

Thanks
 
#2 ·
That's not good. I don't know how much you slip the clutch but that's excessive by any measure. I typically only had to adjust the clutch every 6,000 miles or so when I road on the street and the same for most of my customers I had.

I've put about a 1,000miles on the track and haven't had to adjust the clutch and this is riding in the expert group at a high pace.

The only people I've ever seen go through clutches like that were off road racers and police officers.

I can think of three possibilities.

You have the wrong oil causing the clutch to slip and wear.

You slip the clutch a lot when you ride or adjust the clutch too tight.

There's something wrong with the clutch pack or mechanism.
 
#3 ·
I'm guessing your on the stock friction plates?
How many miles?
You could take out the pack and measure the whole stack and see if its within tolerance. If your constantly slipping your clutch due to your riding habits, your probably ready for some new plates.
 
#4 ·
Hi all, thanks for the replies.

I don't slip the clutch that much really when riding, my habits are probably on a par with every other street rider out there.
I will assume that they are the stock friction plates, i've had the bike from 6000 miles up to the current 8500. I don't have any previous documentation to suggest there was ever any work on the clutch.

One thing worth mentioning, I had the bike stolen last year, and the garage who recovered and repaired it, said that when it was found, the clutch was excessively tight and never dis-engaging. They re-adjusted it back to normal. I started noticing clutch slippage around 3 months after the bike was returned to me.
 
#8 ·
Ho hum, looks like it's that way then.

Is it an easy DIY fix?
Like with everything, "an easy fix" is all predicated on your tool selection, available parts and mechanical experience. I replaced mine last year and if I can do it you should be able to knock it out, its not that hard. A service manual will come in handy, more like a necessity. If you don't have one yet and plan on doing most of your own work, go get one. I've been told by multiple people to change out the springs when replacing the plates, but you can get by if you don't want to. As far as what type of friction plates to get, I have no input on that, I'm using OEM and they are good for me.
 
#9 ·
Thanks for all the input.

I do have the good old Haynes manual to hand (not sure what the US equivalent would be). I do most fairly low-level maintenance on my vehicles.

From what I can see, it looks to be a case of removing the clutch cable and cover, removing the pressure plate and springs, and sliding off the friction and steel plates, the reversing the whole process with new friction plates in place.
 
#10 ·
I'm in the process of doing mine right now (Daytona). Took me all of a few minutes to get the clutch cover off, remove the spring bolts (whatever the actual name is, and pull the plates out. Very easy. I kept everything laid out in the exact order I pulled them out though, so there's no questions about the new stuff going in.
 
#11 ·
If I remember right, the factory service manual (for the Daytona, anyway) has important data about stack height and, if height must be adjusted, how many steel plates are acceptable for doing that and where they can be in the stack. It also has torque specs and probably other information I'm forgetting. Not sure if that's all in the Haynes manual.
 
#14 ·
I cannot see a value in the official workshop manual for total stack height.
Only a value of 2.8mm-3.0mm for an individual friction plate.
Would it be a safe assumption to do the following:
-Take the current total stack height.
-Take the current thickness of each friction plate (assuming below service level)
-Extrapolate what the stack height would be if all current friction plates were at a thickness of 3.0mm
 
#20 ·
From 2011 service manual....sorry for the inverted pic, can't seem to rotate on the phone. Hope it helps.

View attachment 165457

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Fantastic! Though this kind of confuses me because I measured (with a measuring tape, not calipers) my clutch pack at around 42.5 +- .5mm and my clutch had zero grab. I suppose I could have measured poorly, or an individual plate is really worn.

Sorry op, not my thread, just thought it was somewhat relevant given our similar situation.
 
#22 · (Edited)
Well that might explain it.

Total stack height when measured was 39.50mm. Going by the workshop manual posting above, that's around 2mm out of spec!
Some friction plates are worn more than others, with very little 'meat' left on.

I stacked up the new friction plates with steel discs, giving a total height of 42.5mm, which is right at the top end of the accepted tolerance.

Just a couple of questions.
Is it worth cleaning up the steel plates before re-fitting?

The workshop manual mentions that the innermost and outermost friction plates are different to the rest.
Whilst this is true of the inner-most (it has a larger internal diameter), in the replacement pack that I have the rest are the same.
On the stock plates, the only difference that i can see with the outermost plate, is that it has smaller but a greater number of areas of friction material on.
The replacement plates are EBC not OEM.

Also, is it worth changing the springs? They don't look particularly worn.
 
#23 ·
You shouldn't need to do any cleaning on the plates, mine came out looking shinny and new. As far as the springs go, I changed mine at 24,xxx miles. I put new friction plates in last year without new springs and it seemed fine. It wasn't till this spring when I got the new springs in and the bike did seem a bit more responsive. Its hard to say though, I hadn't ridden all winter and had done other work to the bike that could have contributed to what I was feeling.
 
#25 ·
Got round to getting them changed out.
After a bit of swearing at getting the clutch cover back on and getting the rod/lever to marry up, all is good.
Didn't change the springs this time round, but new plates have made the world of difference. Got about half a mile of adjustment available now!

Thanks for all the help.
 
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