My buddy has an 06 400ex we noticed tonight when we went out to the shed to start up the quads since it has been so cold these past few days. Well when he started his up and let it run for a min. at about 1/8th throttle we noticed his head pipes starting to glow right at the head. Could this be from it being so freaking cold out and it hasn't ran in a week? It runs great and always has. it's been jetted according to Dynojet's specs too. He can turn the choke about 1/4 the way on and the glowing will start to fade off. any thoughts for my fellow members? I figure it is due to the cold.