2013 YZ450F: I am hoping someone can tell me why my upper chain roller keeps breaking. The rear wheel bottomed out and hit the underside of the fender for first time in 9 yrs The sag is set to 4 inches. I am a Motocross rider and the tracks have been a little rougher lately than usual. The muffler is an aftermarket Yoshimura. This is the third sub-frame on the bike and it has already been rewelded once. Twice it has broken at the rear muffler mounting bolt and twice where the upper chain roller mounts. Could it be the rear shock/suspension?
Edited by rwebmx, September 07, 2015 - 03:53 PM.