I'm riding a 00 MXZ 700, it often backfires on me when I start it, and I just noticed the other day that it idles at between 2100 and 2400 RPM unless I hit the choke to bring it down. *The carbs where cleaned lately and the bowl nut is tight. *Are these problems comlimenting one another? *I try to let my machine iddle down before I hit the kill switch, but sometime I can hear what sounds like thunder under the hood when I kill the engine. *I have also got a small crack in the Y of the exhaust pipe right where it comes out of the engine (getting this fixed tonight. *Any advice would be great, the backfire is going to give me a freakin heart attack someday.

thanks,

That crack in the Y might cause the engine to idle higher. *I would wait till that is fixed before you do anything else. *

Dont shut it of untill it idles down to 1700. *If you shut it of above that the engine is still spining fast enough to put more fuel in the engine with no ignition. *This fuel sits in the exhaust pipe and with you go to pull it over next time that fuel ignites giving you the backfire. *

It might just need to be kicked down a notch on the idle which is simple to do. *Get the y-pipe fixed then tell us whats going on.

Thanks Machzzzz1, I think you just answered my question also. I put an mbrp trail silencer on my sled at the beginnig of the year and my sled started to backfire, i thought it was because of that. I also turned the idle up on my sled and it idles at around 2400 rpms. So that's probably it.

What kind of fuel mileage are you getting, and do a compression test. *Mine did the same thing and the pistons and rings were bad at 2300 miles. *I would do the compression test first. * Get the pipe fixed also.

Thanks a bunch guys, I'll get the pipe fixed ASAP. *If that doesn't sure it I'll play with the idle screw. *Had the compression tested and it A1. *I'll let you know how I make out.