Hello. I have some problems with my son's beta rev3 50ccm jr bike. The bike gets very hot after some riding. I notice that the fan is not working. I tested with a 12v battery connected to the fan and it works as it should. I made a loop on the thermostat cable. I measure 21v input on the generator when the bike is running, but 0v out to the fan. Could it be the generator? Is 21v input correct?