Motorcycle Repair: Overcharging xl80s

Question
Hi Wayne
Thanks for the pointers on the charging issues, sorry I did not get back sooner had to put the project on hold but back at it again. So you said it was a balanced system I did find that the batt was shot so if I replace the batt it should work fine I hope. I will keep you posted if other issues.


Thanks for the help and new direction andy.

Answer
Andy,
I have included my original reply here.
If you connect a new battery also make sure
all the bulbs are working and check
the voltage on the battery when running.
Anything above 8 volts DC may be trouble.

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Hi Andy,

Many older Hondas used what is called a "balanced charging system".
This was okay when new but as time goes on can cause some
difficulties.

The system used all the components of the charging and lighting
circuits to make sure the voltage was "balanced"

In other words all the lights must be connected and working and
the battery must be good and installed too.
If any part of the system is missing or has a poor connection
then the voltage output will be excessive.

When all is connected the voltage was usually satisfactory
so as not to burn out bulbs so quickly.

As I mentioned if any part becomes detached or a taillight
bulb burns out then the headlight will likely
get too much voltage.

The better solution is likely to find a universal 6 volt AC regulator and
connect it to ground and to the yellow stator wire that
feeds power to the dimmer switch.

More expensive is the small one wire regulator
used on 6 volt Yamahas in the seventies.
These are sometimes found on ebay or such.

http://www.ebay.com/itm/1979-Yamaha-XT500-DT125-DT400-TY350-Regulator-/190921012

If you connect one these regulators to your dimmer switch lighting wire
and ground the frame really good it should shunt the excess
voltage to ground and protect your headlight.

If you connect all your bulbs and battery the voltage might be okay
but you have to check it with a multimeter and make sure
nothing will vibrate loose.

There may be other simple regulators made for scooters or moped
that will work as long as they are 6 volt.

If you try to reduce power with 12 volt bulbs or such
you may find the ignition lacking enough voltage
to run properly and the lights will be dim.

Let me know if you need more info

Wayne S
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