hi guys.got a 05 rev 3 200cc. when it gets hot the fan dies and stops until you rev it up.yes ive changed the stator coils.yes ive changed the rectifier.yes the fan works fine off the the bike with power suplyed to it. any one ever heard of the flywheel breaking down ?? what els could it be??the yello wire coming from the stator is only pushing out around 5-6 volts on tickover im shure it should be more than that. any clues anyone thanks

someone has mentioned on here recently that the magnets can loose there strength but havnt come across it is the earths ok , any breaks in wires dirty connections black wires ( corroded copper ) can you check voltage going into rectifier , could fan be failing and needing more power to operate

Not sure the exact configuration on the year bike, but sounds like a faulty voltage regulator taking the voltage down. I have had this on a beta before. Seems some years have an integrated VR rectifier for the fan though?

ok guys the reason i thought it was something to do with the flywheel this beta was kicking out 5-6 volt on tick over. i got a 02 beta aswell.so tested that and got 8-9 volts. so i took the fan off the problem bike. ran it on just 3volt for 10 mins and all ok fan worked fine.untill i put a heater on it.yess the fan nearly stoped. £130quid later all good. so i took the old fan apart. the whindings conecting the power had burnt out but not totaly so yes it would work until it got warm then stop. well atleast the elictrics are good on this bike now.lol thanks guys