jwhracer Posted October 6, 2005 When I start the bike up and after it warms up I hit the throttle it back fires and pops. I have cleaned the carb and all the jets. i have went richer on the main jet and tried messing with the needle and air screw and nothing helps. Any suggestions. Share this post Link to post Share on other sites
ButchWR250F Posted October 6, 2005 Sounds like you're a little lean on the pilot jet. Check and see which one you have in there and go up a size. I run a 45 in my bike, and it doesn't do that at all. Of course you can have an exhaust leak either at the head or where the muffler attaches to the pipe right behind the kickstart lever, and that will cause it to backfire too. So I'd check for an exhaust leak first, then if it's OK, then do the carb. Share this post Link to post Share on other sites
