yz_rider_44 Posted April 2, 2010 i just bought a 2005 rmz 250, when started for about a minute the pipe gets glowing red! i too afraid to drive it, it has a fmf bowerbomb on it, is the jetting too lean? Share this post Link to post Share on other sites
downonmonday Posted April 2, 2010 It's running lean. I have the full Yoshimura system and I had to bump my main up 2 sizes, my pilot 3 sizes, and drop a notch on the needle. Everything varies due to your environment/elevation, but it is running lean. Plus, these bikes get hot fast without moving air. Share this post Link to post Share on other sites
Eggbert Posted April 2, 2010 A huge air leak may be causing it to run that lean, especailly if it was working OK before. Look for a rip in the intake between the carb and cylinder. In a car enigine, I'd be looking for a broken vacuum line. The idle should also be high if it's an air leak. Anyway, just another thought besides jetting. Share this post Link to post Share on other sites
downonmonday Posted April 4, 2010 ^ True, didn't think of that. Share this post Link to post Share on other sites
agf racing Posted April 8, 2010 Tight exhaust valves can cause that also. Share this post Link to post Share on other sites
