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Clutch slipping?

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So I have an 09 250F that has some mods including a Williams motowerx ported head with cams, high compression piston, pipe and I think that's about it for the engine.

Anyways I noticed that after I've been ripping the bike at the track for a few laps, I'll stop for 5 minutes and chat with the buds and when I fire it back up it seems like it's pulling harder than before when it was at hot track ripping temp. It has the oem clutch in it still, that stuff is all stock. The only other thing I did was put in a CP, 2 ring 13.5:1 piston.

Thoughts? Clutch Slipping?

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I pulled the clutch plates and they look good and within specs, the friction plates look good too, no discoloration or warping.

So I guess I should order some heavy duty springs and give that a shot?

Anyone?

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Give some Moose springs a shot. That's what I am running this season. I have also run the Pro Circuit springs in the past, but you need to be the hulk by the end of a 20 min moto to pull the clutch in.

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All of the YZ250F's I've ever built up had clutch slipping problems afterward. The stock clutch seems to be borderline too week, just barely strong enough with a stock engine. Sometimes stiffer springs fixes it, but I found on my current bike that stiffer springs just caused the clutch to chatter under hard acceleration. I put in DP clutch plates with EBC heavy duty springs and it took care of my clutch issues.

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All of the YZ250F's I've ever built up had clutch slipping problems afterward. The stock clutch seems to be borderline too week, just barely strong enough with a stock engine. Sometimes stiffer springs fixes it, but I found on my current bike that stiffer springs just caused the clutch to chatter under hard acceleration. I put in DP clutch plates with EBC heavy duty springs and it took care of my clutch issues.

Thanks, that will be the next step.

Any issues using the steel plates? Can you even tell the difference?

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Thanks, that will be the next step.

Any issues using the steel plates? Can you even tell the difference?

I've tried stock metal plates and aftermarket plates, I can't tell the difference. The biggest difference seems to be in the friction plates. However, friction material that grabs better, like high performance brake pads, tend to wear out faster than stock (however last much longer than slipping stock components). That is the trade off you get.

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