dylan250x Posted April 9, 2010 hey i have an 05 crf250x and i recently took the head off of it to replace the valves. and noticed that i had alot of carbon buildup on the top of the piston. then i took my finger put it ontop of the piston and noticed that i could wiggle the piston back and forth just a little bit to each side. is it normal to have a little wiggle room? and if so how much? thanks this would be very helpfull Share this post Link to post Share on other sites
juliend Posted April 9, 2010 It's called cold clearance, and it's necessary to prevent the piston from seizing in the bore when it heats up and expands. As for what this clearance should be, it's listed in your service manual as piston/cylinder clearance. Share this post Link to post Share on other sites
dylan250x Posted April 10, 2010 ok thanks very helpful Share this post Link to post Share on other sites
