replacing pistons

Joined
Jun 9, 2001
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#1
I have a 1995 KDX 200 that I just bought and I want to replace the piston. Is this an easy task or should I take it to the shop? I bought the service manual but it has not arrived however when it does come I want to do the work myself. What are some key tips on replacing the piston and putting the new rings on the piston. I bought the Wiseco piston kit. Thanks
 

MADisher

Grand Data Poohbah
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Apr 30, 2000
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#2
It's really not that hard. Especially if you have the service manual and are partially mechanically inclined. If you've never done it before. I would advise you letting someone else expect the cylinder once you have it taken apart if you aren't comfortable with it.

There is no point in putting a new piston/rings in a scared cylinder. (But I'm sure you knew that :)

Most folks don't have the tools to check it for roundness, etc.

I've done it on my RM but not on my KDX so far.

Hope that helps.
 
Joined
Dec 10, 2000
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#3
Replacing the top-end is fairly simple if you follow the directions in the manual. Once you have everything apart, make sure to service the powervalve assembly and deglaze the cylinder. Measure the ring end-gap before installing the piston and rings, if the gap is too small serious engine damage can result.

The Weisco piston is an excellent choice ( I use them exclusively), but you must be sure to break it in properly and carefully, or you will be rebuilding it again due to seizing it. The Weisco is a forged piston, and is very sensitive to proper break-in. Did I say break it in carefully? I can't stress that enough.

You definitely need a good torque wrench to do the job properly.
 
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Dec 21, 2000
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#4
Caution!!
Be sure and pay careful attention when removing the nut that connects the power valve actuater rod. It has left- handed threads. Just take your time and keep your computer handy in case you need more advice.
HAPPY TRAILS,
Keith