misfire

Need ideas! stock 2011 ape xtx ran perfect, installed a new MBRP muffler and now has a misfire only on near or wide open throttle, no trouble codes, all appears normal.

Hi so i have a 2010 yamaha nytro mtx. I have a code 81 that keeps poping up and a misfire on cylinder 2. I was riding in deep snow and then code 81 poped up when i was riding also that weekend after a 150mile ride it started to misfire at idle and fluctuate between 1500 rpm and 1000rpm. I...

Well I've had my first problem in 18,000kms of riding phazers. 5000 on the 14 I ride now. Today, slowly started missing here and there. Stopped, checked everything I could. Started ok (cold already as its -37 with wind chill today) once moving it really started breaking up. Being out on the...