My '98 YZF Has been acting up and I dont know what to do. It pops and backfires and then dies. Then if I change the plug which is carboned up it will usually fire. But the last couple of days it keeps popping and stalling until up to full operating temp. (hot) then it stops. Then I left it sit for a while and rode again and it didnt pop but it suddenly stalled and wouldnt fire again (probably would have with a new plug) HELP!!! I love the bike but this is such a pain!!!. Incidently it usually doesnt do it in warmer weather.