I recently did some work to a friends kx100 because of a scaping noise from the engine. I pulled the top end appart and the cylender was fine, the rings were good and the piston was good. There was no sound when i turned the crank minus the to end by hand. I cleaned the power valve thinking that might cause the noise and put it all back together. The sound is still there upon firing the bike up. It sounds like the piston has no lubrication and is scraping up and down the cylender walls. Any ideas what this could be??
