Charging issue... I think

Hello all

I am having a charging issue with a 1983 midnight maxim 750

Little back story on the bike

it has 32k miles on it, it was owned by my cousin for 15 years but never ran while in his possession. that concludes the little back story... its all i know about it...

I am having charging issues with it. the bike will start but the voltage stays between 12.3 and 12.65 at idle. stays at 12.65 under throttle

i went through my trouble shooting that i found on this wonderful forum

wiring into the regulator (new)
red wire has constant 12v
black wire ground
brown wire 12v switched

.46 ohms between each stator wire (which is new btw)
4 ohms between the rotor rings (also has new brushes)

basically im wondering if this can all be caused by a bad cell in the battery?

after putting the battery on the charger it shows 12.8v

Im not sure what else to check or if my testing condemns the battery

Could it be that simple or am i overthinking it?

Any help or opinions would be much appreciated

 

Did you check your alternator brushes, there is enough mileage there to wear them out

 

I replaced them with new ones from Ricks.

 

you need to test the voltage at the 3 white wires going into the regulator /rectifier
do you have a multimeter?
if so, test for a.c. voltage with the plug removed from the rectifier, with the engine running, test across each 2 wires in turn, you should get around 20 to 30 volts across each pair of wires, if so suspect the rectifier, if not, work back to the alternator, check wiring and connectors,

 

Interesting. I had the same problem and brushes fixed it.

 

did you clean the copper rings?