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kx100 power valve mod?

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does any one know anything about an after market power valve mod for the kx100? does it work well? worth the cost?

ive read a little about it on Eric Gorrs web site

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There was discussion of an aftermarket powervalve mod for a KX100 less than a week ago, right here in this very "Kawasaki 2-Stroke" forum. :lol: You don't even need to do a search. Just start looking for posts with KX100 in the title and read them. I'd suggest going through like the last 10 pages of posts, reading every one with KX100 in the title. You'll learn a lot.

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We had one but my posts are ancient on it. Get with JBFL, his son currently has on in his 85's. Can't remember who's PV it is but you have to have the govenor spring to go with it.

probably was one of the best mods I'd done on my sons 100. But that was awhile ago. No longer have the bike.

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I've only used the softer spring (I think), been doing waay better tuning with my motor guy. Trying different chamber and squish setups, can't believe the changes just the head makes.

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As stated it works very well, we use 'em on the 85's & 100's with and without the softer spring that Pro Circuit offers. Better,easier,and simpler design then the puzzle pieces Kawi has. Both Jim Saylor of JMS performance and ProCircuit sell the 1 piece valve.

Good luck and enjoy

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oops, I stand corrected on my post or actually more clear. you can use the stock spring with the aftermarket PV, but if you use the spring, you have to have the PV. It's lighter than the stock PV.

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In our experience, the JMS power valve that Eric sells works better then the PC. 2 piece valve. Which are prone to break. I would try the PC governor spring first its the cheapest bang for your $. If money is not a concern, send the top end to Eric & let him do his magic, port,polish & reshape the combustion chamber along with the governor spring makes for a reliable powerhouse. my. .02¢

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The pro circuit powervalve requires the use of the softer spring while james' valve (jms) utilizes the stock spring. James has done dyno runs with both and his does outperform the pc valve.

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It depends on what you want out of it, looking at the design of the JMS, it will increase bottom end dramatically, but at some top end expense. The valve is a big slug that lowers the port probably a good 1/8 inch or more for low end grunt, but at the same time, when it is in the high speed position, it is a much larger restriction with sharp corners in the exhaust flow. IMHO, you will loose a few ponies on top, but the mega low end gives more area under the curve.:lol:

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Does anyone have a picture of the JMS valve is it a one piece of solid aluminum? with a piece on it to hook the actuation arm for the powervalve shaft . I would assume then it must not have a stopper in the bore like the original or the pro circuit piece ? It would seem to me that if it gummed up in the bore at all then it may not move ? I think though for my purposes of trying to build a trail bike for the wife it might be the hot ticket as I don't really want any top end power .

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