Hi I own an 05 yfz and it has a fmf 4.1 exhaust with a rev box, yamaha racing intake, and a jet kit. For some reason the exhaust shoots out flames when its revved up and at mid range driving the quad doesn't feel like it has as much power. So I was wondering if anyone could help. I'm thinking that its the jet kit that needs to be tuned or the rev box needs to go. Any suggestions?