Voltage Regulator & Stator

 

Symptoms

 

Weak battery, lights dimming, VR gets extremely hot, burnt smell from left rear tail, rotten egg smell and acid leaking from battery boiling over. 

 

Checking the Voltage Regulator

 

Get a volt meter and check the voltage across the battery while the engine is running at 3K RPM's. You should get a reading of 14.3 to 15.3 volts. Any less or more and the regulator is bad.

 

Checking the Stator

 

After checking the Voltage Regulator, check the Stator or alternator or generator, whatever you like to call it, to make sure it's the VR going bad. On the VR there's a plug with 3 white wires in it. Pull that and get your multi-meter out. Set it to Rx10 and check the resistance of the top white wire with the second white wire, then the top wire with the third white wire. You should get a reading of 0.31 to 0.37 ohms. Any less or no resistance and the stator coil is bad. Normally though, it's the VR that's bad.

On the left side of the bike is the stator..the 3 wire plug coming out of the sidecover disconnect it and put the voltmeter on AC volts...start bike..put a lead from the meter on one of the white wires (all 3 are white) and the other test lead on another white white wire..Have someone rev the bike to a steady 3000RPM..do you get at least 40 ac volts?? if you do repeat with the other white wire...same results?? If you get 30-40 acvolts on both legs but the battery is not charging at the specified 14.3-15.3 then the rectifier/regulator is bad.