I put a mbrp trail silencer on my sled about a month ago, which is a 01 700 mxz for those that dont know, but anyhow since then when i pull the cord to start it alot of the time it will backfire rather than start. I check my plugs at least once on every ride at some point to see how its burning and its always a nice tan color, and when i first put on the silencer i checked my plugs about 20 times at different speeds to check the burn and its was still a tan color burn, so i dont think its caused from a lean condition , nor a rich condition, or is it because of less back pressure with the straight flowing can?? so all i got to say is WTF?? What do you guys think?? Geeez that was my longest post yet!!!