When I first purchased my 02 Raptor last feb or so, I noticed the fan would come on after I shut it off and sometimes while I am idling. Since then I purchased a R4 Serries white bros pipe and jetted the carbs and I have never had the fan come back on since. Just wanted to know if any one else is having a problem like that? A buddy of mine also purchased a Raptor last month and he too experienced the same thing with his. He also went to the same pipe and jetting. I thought maybe the sensor goes bad after a few hard rides. Any feedback would be greatly appreciated.

 

Could be that after the new pipe & jetting, your motor might be running a little cooler because of increased air-flow through the motor. The reason why I'm thinking that is because when I let my '02 YZ 426F idle for a few minutes at night, about 10 inches of the header pipe glows cherry red...then when I rev the motor the glowing goes away because of the increased air-flow through the motor. Later......

 

I was thinkin the exact same thing a while ago - couldnt remember the last time I heard the fan !?! Well, now with summer upon us in the dez the temps are near 100 degrees. Sure enough, the fan kicks in fairly regularly now....