a couple of months ago i changed the thermostat on my 06 pro as the bike was overheating as the fan wasnt coming on. it was fine after that and all working as it should untill the other day when i noticed my bike was overheating again and the fan wasnt coming on. i bypassed the thermoswitch first and it still didnt come on so i took the fan off and tested it on a car battery and at first it didnt work, but then it started starting then stopping, then it started running pretty much constantly. i put it back on the bike and it wouldnt run (with thermo bypassed) i tried spinning it to try and help it to start but it didnt. my question is is it possible for the motor to be on its way out and work whilst on the car battery (it was intermittent when i first put it on) but then not when i put it on the bike. do people think a new motor would solve my problem. thanks in advance.

can you check for good voltage once the stat is croossed and good earth ,possibly with a light to determin getting good power source to run the fan ,the car batt would find it easier to run the fan if its on its way out than the bike would

Your fan is knackered. Use a groupner 500e motor to fix it. There's a thread on replacing a txt fan motor on the forum.

I got a new fan unit but it hasnt solved the problem, ( I tested the new fan on the slim chance that it was faulty but it worked. It shouldnt be the thermostat because it doesnt work when I bypass it and I put a new one on a couple of months ago. Is the only thing it could be the voltage regulater ( is this the silver box under the tank that is bolted to the frame?). This looks to be ok, is there a way of testing it, thanks

You should have checked the electric feed to the thermo switch before buying a new fan, trace all the wires, check connections and most important clean the earth points.

Not sure if you have regulator or rectifier or both but these rarely fail, its more likely to be a connection or melted / pinched wire.

TLTEL