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Clutch slipping on a 470

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Anybody else had this problem?

I don't know how many miles/hours are on the clutch that's in my motor right now but it slips like mad at wot. It feels as if I was spinning the rear wheel but that's not the case.

Is the stock clutch too weak for the 50+ hp or is it just worn out?

What would be a good heavy duty replacement?

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Also, if replace, what to replace? Springs, basket, complete clutch?

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Instead of just replacing parts, you need to measure them to see where the fault lay. You need to accurately measure the spring free length and the fiber friction disk thicknesses, assuming the clutch is assembled properly.

Out of curiosity, how many miles are on the clutch and what kind of riding had you been doing?

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Thanks for quick replies guys.

I'm taking the bike out for a ride on knobbies tomorrow and then I'll inspect the clutch.

I have no idea how many miles are on the bottom end. It's an ex-factory Yosh motor. It was ridden by Steve Hatch at WORCS in 02. That's all I know.

Probably ridden hard off-road. It got a new crank and bearings at some point but I can't tell how much it was ridden afterwards.

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Must be all that extra power from the new pipe! :)

Did you get the screen out?

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definatley measure.

springs are probably all thats needed.

Will do. Thanks Eddie.

Must be all that extra power from the new pipe! :)

Did you get the screen out?

I did get the screen out, it was easy. During the process, I learned that the Ti Yosh muffler has only a 1.75" core.

The GSX-R can I had on before has a 2" core. I might try to track another one down and shorten it. Although, I saw Eddie's dyno graph and it only showed about 1hp difference between those two setups. It's weird. I felt like the bike pulled much harder with the SSW/MRD/TRS combo.

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That core is tapered, smaller at the endcap. I don't remember how much, though.

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Eddie

Why not EBC or Barnett?

Just curious as I use EBC kevlar plates in a pretty big hp FZR with no problems at all...

I also have a complete set of kevlar plates, steels adn springs to go in my big block.

The motor has about 4k on it and slips at WOT...

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I just pulled the clutch out and the free spring length is only 33.3mm..?

I read that the service limit is 49.9mm

How come there's such a huge difference? :)

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This was a Yoshimura factory motor. The rest of the clutch is in spec. Just the springs are super short.

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I didn't count the plates but the set seemed like a good fit.

The clutch works great except for slipping at WOT.

Does the kicker motor have different specs? I doubt it does but I wonder.

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How come they're so much shorter than the service limit?

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