I don't have a 636 but I assume they still use a thermostat to control the coolant flow. check that to see if its bad - or just replace it since they are cheap.
the thermostat can fail in many ways and one of them is not opening enough to cool it.

 

My fan comes on around 215 or so. When its in the mid to upper 90's out and I'm at a stop light it gets up to 230 then jumps back down to 215ish. The only time I've seen it flash the hi temp was when I shut the bike off and key is still on the "ON" marker.

 

The fan will only stay on while the bike is running. FYI. At redlights I've seen my bike get up to around 222 - 224. I have engine ICE as well and it DOES work when I'm riding, not so sure about it idling though. I notice it is running 10 degrees less then it used too. To make sure to get all of the air out of the system... take off the radiator cap and let the bike idle for a little bit. This should get the air out of the system. If there were air in the system you would see spikes as you were riding... like it jump up to 215 then shoot back down to 180 or something.

 

guessing its out of warranty ?

 

thanks guys for your responses. it ended up being my cluster apparently it has its own attitude and works fine at certain times then says nope not going to work right now any way guess i have to get a different used one. Anyone know of any?

 

my fan comes on at 212 and will stay on till ive been riding for a few minutes. not sure on the newer ones though.

 

it has a salvage title? how bad was it wrecked?

 

Well it started to go over backwards, then from what we can count on the video it rolled at least five times. amazing part after getting new rear rim strightening the front the thing drives better than it did new (had a bad head shake). I ride it every day now as my work vehicle and then just learning stunts.

 

no **** thats surprising to hear. ok i was wondering why you bought a dam wrecked bike. what year is it again?

 

I bought it new, its an 06 it had 4200 on it when i went over and now i basically have it set up to do stunting, I will be looking at a new bike next season but the fact that i am not worried about wrecking this one makes it a lot eiser to go out and enjoy myself. hell the first ride my girlfriend took it for in a parking lot she stopped to talk to me and just set the bike down on the cage. (the only time i will let someone else ride is with this bike if they wreck anything they would have to diliberatly do something wrong.