KX100 experts, need help

I just got a 2006 kx 100 and I found a good deal on a cylinder, the guy says it will only fit 98-04, Is there any chance this will fit on my bike? I just want the bike to run know the bike will run fine, I don't need all the updates on the new cylinders. any info would be awesome thanks.

Well I am no Expert but the Wiseco site says they use the same piston. Lucks racing says the 98 to 2009 are the same.

So as far as I can tell they are the same.

While it may fit, there is always the possiblilty that the factory upgraded the cylinder in some way between '04 and '06 - even though you say you don't want the updates - if the bike runs better and was already tuned for the newer cylinder, you may be going backwards and lose something you were hoping to keep.

I'm sure one of the gurus will pipe up with some facts.


What happened to your 2006 cylinder that you are not using it?

I picked up this bike from a guy that got it in a trade and didn't even know what it was. He told me it was an 85. It came no cylinder ( I have no idea why it was not included in the trade) I got there and I offered him what I had in my wallet which was only 250 and he said take it. I knew it wasnt even blown up either cuz it has the piston still attached and it's in good shape. The seriously looks like it has been ridden about 5 times.

It'll work fine - the casting is identical.

Yes it will work but there are some minor differences. Nothing to be worried about though. Actually 98-05 were the same and 06-09 were upgraded with a beefier exhaust port and a vent on top of the powervalve. There weresome minor port changes but not enought hat it wouldn't work. The big difference in the cylinder heads. 05 and earlier have a deep step combustion chamber and the 06+ were more open and have a different squish area. but either will work on any bike.

If you have anymore questions, let me know. I have both right he on the bench. My sons is an 06 getting a stroker crank and we have an 05 cylinder and head out to 54.50mm to make a 112. the 06 cylinder and head will be going out to get sleeved for the same as well so we have a back up topend.

If this might be something you're considering, make sure you realize the cost. +2mm Crank, bearings, seals, gaskets, etc=$250, have cylinder sleeved, ported, powervalve cut, etc = $400, piston kit for 54.5mm=$165, machine head for extra stroke, @ $65.

Look on the kids face when he can pull the front wheel in all 6 = Pricele$$

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