[SethRobinson]

I have a 1973 Honda ST90. I’m new to forums so I apologize if this is on the wrong thread. It only seems to be charging 4 volts to the 6 volt system. The bike was garage kept and only has 900 miles on it. The entire engine was rebuilt professionally and it ran good for about 2 days after that. With a freshly charged battery it fires right up first kick, and runs for a minute. Magneto/stator look good and no corrosion. What could it be? Wiring under the seat looks rough and is all electrical taped up so I’m not really sure. Thanks!

 

[tmas]

Welcome to Planet Minis....
First have a look at the wiring under the seat. Remove all electrical tape and inspect the connections. It could be as simple as a bad connection.
tmas

 

[SethRobinson]

Welcome to Planet Minis....
First have a look at the wiring under the seat. Remove all electrical tape and inspect the connections. It could be as simple as a bad connection.
tmas

Thanks! I’ll definitely do that. The wiring under the seat looks super rough and it’s all covered in electrical tape. Gonna get some spray cleaner and open the wiring all up from the tape.

 

[dipoco]

Seth, after checking/cleaning the wires and connections, disconnect the battery, run the engine, measure the voltage in AC mode coming from stator first, then check again in DC mode after regulator/rectifier, it's has to be more than 6v in mid acceleration. How do you see the light running without battery?. They should light up bright in high rpm.
Good luck. D.