So on my cr500 I kept think I was fouling plugs but they always looked great... it turns out if you vent line on you gas cap gets iced you will vapor lock the bike...so my primer would get it started but it kept cutting out... cap comes off and a woosh of air... I think I am going with a ventless cap. This seems simple but it was an hour on the mountain scratching my head before this was figured out..
