I have a coolster 125cc. Model xr8b. When I put it away it ran, sat for about 3 months. Needed a battery. Bought a new battery. When I hooked up the new battery smoke started coming out of the left side engine cover where the alternator is. Took the cover off, the alternator lower winding setup was heating up, getting extremely hot. I bought a new one thinking it had a short in it but the new one is doing the same thing. Any ideas on what is causing the alternator winging to heat up like that??

 

bad battery. could have a short internally.. did you try putting the old battery back in and jumping it? Did you fully charge the new battery?

 

Yes I had another battery and put it in, same exact thing happened. After reading some posts That had the same problem and the voltage regulator as the cause, I unplugged the voltage regulator and the problem went away. Thanks for the response.

 

If the stator is shorting to ground thru the bridge rectifier it will indeed heat up and fry the stator and rectifier. Remember the bridge rectifier is a circuit of diods that are tied to ground. If the stator heated up to smoke, it's probably shot. There is a varnish around the copper wire windings. Removing the insolation on the copper wire and you have a problem.