Motorcycle Repair: 1970 honda ct90, full wave bridge rectifier, honda ct90

Question
Hello Bill my name is ken I just bought a 1970 Honda ct 90, runs good looks good but it has a charging system issue the AC generator is putting out voltage but it is putting out to much so I tested the original rectifier and it had a bad diode so I replaced it with one from radio shack. But it did not make a difference at all and I don’t know what to look for next. What is the normal voltage out put from the rectifier to the batter so I know what to look for.                   

                                             Thank you
                                                    ken  

Answer
Ken, Did you install a full wave bridge rectifier from RS on the bike or just a diode? I'll assume a whole unit. The OEM Honda parts may have a certain current limiting factor built in due to the design of selenium parts.. or not. The other part of the rather skimpy charging system components is the battery. It must be a fully functional and fully charged battery to act as a reservoir for the charging system output. If it has shorted cells or is sulfated, the charging system will just blow through the battery and over voltage the rest of the wiring, blowing out light bulbs, etc.

Normal battery voltage should be in the area of 6.5 to 7.5v DC, under running conditions.

When the bikes are run on an open circuit scenario, the stators can pump out 20+V AC, which takes down any light bulb in the system. All the bulbs should be functional to help balance the load/output voltages.

Bill Silver