volts dropping...

[RMS621]

Bike and motor info
1975
277 Rephase
700cc
Pamco ignition
Mikes XS PMA

I just finished this build, the motor only has about 300 miles on it. I have never had a problem like this until today.

I do have a 20a fuse between the batter and the regulator.

A constant pain in my ass... Thinking the regulator rectifier is fried. I have 12 volts at idle, but as soon as I rev the engine it drops to 9v. I omh tested the stator I was reading .8 on all 3 wires. The battery was just replaced right before the new motor went in. Was riding today and it started to pop and back fire, losing power. Stopped at a buddies house. I didn't have any tools to really check anything, let it sit for about an hour and then tried to drive home. I made it about a mile down the road and it just wouldn't rev passed a 1500rpm. Got it home and still can't figure it out. Any ideas??

The other think I noticed if I have the key on my headlight and tail light almost drain the battery instantly. Going from 12.19v dropping down to almost 2v. Pulled the fuses for them both and have been testing the charging system with them off.

Is there a way to test the regulator on its own?

 

[DogBunny]

You tested the stator, but how about testing the rotor?
If you have the original regulator, you should just go ahead and get the Advance Auto R292 replacement. Money well spent, even if it's not the problem:
http://xs650temp.proboards.com/thread/3246
Only other thing it might be is the battery -- not sure if a dying battery ever behaves this way, just another thought.

 

[RMS621]

I have a full PMA swap. So nothing is stock.

 

[jamesgs4]

I am having the exact same issues, but am running a sparx capacitor. my next step is sending my stator to get tested.