Here's the deal: I have an '02 Raptor with minimal mods. Pro-flow kit w/K&N, no lid, 150/155 mains, Big Gun full exhaust. I recently finished my practice mx track and have been running it hard in 1st-3rd gear. It's been overheating bad lately. I run water wetter in it and that seems to not make much of a difference. The oil is clean, I'm not losing coolant anywhere(that I can see). The jetting is okay because the bike runs fine normally and does not break up until it gets hot. Even then, it isn't until de-celleration, i.e. when I let off the throttle it starts to break up.

I ran it at Rumble on the Ridge (a 30 mile, muddy poker run) two Saturdays ago and had no problems. I even ran the trail twice. I really don't hear my fan kick on any more, but would that be keep the engine in operating temps? Could I have a more serious issue on my hands?

Here's the dumb part: If I change my gearing, will that help? Right now I run 12/42 and lug the motor a lot. If I go to 40 in the rear and work the revs a little more, will that change things any?

I'm thinking about making some minor improvements, like a new top-end rebuild, mild cam, different pipe, a rev box and larger radiator. I need some help guys, any ideas?

 

Just my opinion....but I don't think gearing will make much of a difference.....I recently had the same problem with a golf cart...I know I know...not the same...but I found mud on all my electrical connections and some of them quit making contact...after cleaning them...it ran better than ever before...I thought it was a carb problem...so just as a process of elimination...check all your connections....and some guys wire their fan to stay on all the time...at least here in Arizona where we sometimes ride in 110 degree days and 90 degree nights.mud is killer on this stuff.(just a thought)

 

your fan only matters at speeds below 20-30 mph. I would make sure the radiator isn't covered in mud. also do you have water flow?

 

Does the temp light come on?

 

Sounds like the fan is not working. Check the thermostat too. Adding engine ice and a shade colder on the plug will help too.

 

I don't have the temp light anymore, I eliminated that with my switch/key. I don't think the fan is working either. I'm starting my winter tear down this coming weekend, so everything will be gone over.
The radiator is clean. I'm not sure about flow. I'm hoping it's just something stupid like my thermostat or my impeller.