I recently bought a new leftover 2005 KDX220 and I wanted to thank you guys on this site for all the useful information. I never would have known about the piston issue but thanks to this place, I did. I just got done replacing the stock piston with a Wiseco and luckily it was not cracked and there was no cylinder damage. I only have about 70 miles on it so I wasn't too worried, but the idea that the piston was basically a time bomb waiting to blow was making me nuts. The job was pretty easy for the most part but that reverse threaded nut on the advancer shaft was a bear to get off. I can't believe someone actually got it that tight. Also thanks for the warnings about supporting the shaft so as to not break it down lower in the motor. I used a 6mm wrench to hold it and it worked great. After reassembly it fired up in 2 kicks after a few slow ones to let the piston and cylinder get lubed up a bit.
I can't wait until the weather starts getting nicer again so I can break it in and have a blast! Thanks again!
I can't wait until the weather starts getting nicer again so I can break it in and have a blast! Thanks again!