What could cause it? I let it warm up for about 7-10 minutes and when i walked out it was glowing red. i shut it off and let it cool down. started it back up. nothing happened so i rode it for awhile and it did just fine. i rode for about 10 minutes. even got on it a couple of times while racing another 4 wheeler. when i stopped i looked at it and it wasnt orange or anything. what could cause it? its stock except for a uni filter. please help.

I'VE HEARD OF THIS A COUPLE TIMES AND IT'S EITHER THE FACT THAT YOU ARE RUNNING TO LEAN......OR THE FACT THAT IT'S A YAMAHA!


HONDA ALL THE WAY!

THIS IS NORMAL FOR START UP, THIS IS A RICH CONDITION FROM CHOKE BEING ON. UNBURNT FUEL WILL CAUSE OVERHEATING IN THE EXHAUST CHAMBER, DONT BE ALARMED! PPROLONGED CHOKING WILL CAUSE THIS AND IS VERY NOTICEABLE IN THIS COLD WEATHER.
SUMMER YOU DONT USE CHOKE AS MUCH AND YOU WONT NOTICE IT AS BAD. JUST IGNORE IT. YOU CAN CALL YAMAHA TECH SRVC AT 1-800-255-6756 IF YOU HAVE ANY DOUBTS.

TIM

Wideload is correct, this is normal, especially in the winter. If it does it while riding though, you may have a jetting problem. Did you make any carb changes when you put on your UNI filter? By doing that you leaned out your mixture so some jetting may be required. My Stock warrior was lean on the bottom right from the factory, after mods, it was really bad.

Not to worry all atv's are that way,it perfecly normal.

it probably lean, you may just need bigger pilot jets. Dont allow prolonged or repeat performances.
You can just imagine whats happening to that aluminum piston just inside the head. much more and it will be a melt down. Also you can assume that its warmed up enough well before it glows. Riding cools it, due to airflow. if it does it while riding you better get it jetted.