Motorcycle Repair: REGULATOR/RESTRICTOR, stator rotor, 1981 honda cb900

Question
HOW DO I CHECK TO SEE IF MY RESTRICTOR IS WORKING PROPERLY, ON MY 1981 HONDA CB900? THE BATTERY REPEATEDLY LOOSES CHARGE.

Answer
Go to www.electrexusa.com for complete instructions on charging system troubleshooting and maintenance.
http://www.electrexusa.com/electrex_fault_finding.html

Honda DOHC fours and sixes all use a similar system, that includes the regulator/rectifier, stator, rotor and contact brushes.
When everything seems to be okay and it is still not charging, the usual problem is that the rotor windings are going open when the rotor heats up from engine heat transfer. Check the rotor resistance when the engine is COLD and again when it warms up. Replacing the rotor is generally the fix if the brushes are okay and the reg/rectifier isn't smoked. Check the wire harness connector at the stator, too. They often get corrosion built up and they overheat the connectors damaging the stator and/or the reg/rectifier. Some rotors have been known to shear the locating key on the crankshaft, causing them to spin on the end of the crankshaft, but that is fairly rare. You will need a special removal tool for the rotor removal and sometimes the task is very challenging.

Always start with a fully charged battery when doing testing.

Bill Silver