Motorcycle Repair: twinstar 185 electrical problem, regulator rectifier, yellow wires

Question
I have a honda 1978 twinstar 185 and the battery only stays charged for a week or so.  I bought a new battery and it died in a bout a week.  I tried to charge both batteries but they will not take a charge.  The charger indicates "trouble".  I don't know what to do.  I hope you can help.
Michelle

Answer
Michelle,
It sounds like your charging system has some
problems. If you run a battery dead, it is sometimes
hard to get them to charge. Try hooking the
new dead battery up to the charger along side
another battery with some charge in it.
This will help the dead battery get started.
If this doesn't work, the battery is likely
faulty.
You have to install a good battery and then
check the battery voltage when the bike
is running. It should have about 13.5 volts
when you speed up the engine.
If it doesn't have this, you have to
check all the fuses and connectors.
Lastly you have to check the stator output
and the regulator/rectifier for problems.
The stator usually has 3 yellow wires coming
out of the engine.
You disconnect it's connector
and check with a multimeter set on "AC"
voltage. It should put out 50-60 volts
between any two yellow wires.
If this checks out, the regulator is likely
faulty.