So, I had been meaning to change the plugs anyway, so while I was in there I figured I would swap out the thermostat considering it was cheap and simple to do, it didn't solve the problem however.

Here's what's going on.

• Bike will reach red temps and overheats.
• Fan does not come on
• Fan fuse is good
• Thermostat is brand new

This leaves only two possibilities right? One being the thermo switch and the other the fan motor? Is there a good way to test the thermo switch? I read something about jumping two leads together, but this switch only has one lead...

This is the switch

 

can you jump the fan? to see if it works.. maybe run a manual switch to run it when you want it... personally I'd just replace the thermo switch.. $38.63

 

Stupid question but you have checked the coolant level?
If you want to test whether the fan works just pull the lead off the thermo switch and short it to ground. If the fan cuts in then you know it's the switch. If it doesn't and you've definitely got voltage on the lead then the fan motor is shagged.

 

The fact that it overheats has me worried.

Do you have coolant in your oil?

 

What does the raiator feel like? Is it cool in the middle? What about your water pump. If its jumping that high that fast its possible you have an airpocket. Should be an article somewhere to find out what ohms the temp sensor should be at.

 

They jump up real fast when setting idle in traffic, especially when the fan doesnt run. The switch is basically a normally open switch and when it reaches temp it closes and gives the fan the ground it needs. As long as you have power to the fan then just unplug the wire from the switch and ground it with the key on and it should run. If it doesnt check you have voltage on the positive wire. Its not uncommon for the fans to die on these bikes.