My battery left me for dead today. Thanks, to AAA premier for the jump start!!! Rode it home approx 25 miles without any issues. After getting it home checked the battery and it was 8.7 volts 9% charged. I promptly charged the battery to 100% 12.8 volts and began testing. I started the bike and the generator is only showing 13V...at idle and increase rpms to 2500 it shows 12.3 I tested the stator and it showed .7 across all three legs. The book says .43@ +/- 15% @65 degrees. I'm assuming this is a good reading??? While the bike is running the stator is showing 6.3 volts per leg??? The grounds are all good and I have a ground running from the voltage reg to frame to battery. I'm assuming its the rectifier gone bye bye??? Thanks for any help....Mike

Gen 1 or Gen 2? This gives us a better chance of knowing what you are looking at.

OOPs! My bad, just saw your profile info. Gen 1 1996 model

How old is your battery?

How do your battery cables look? Are they corroded? How does the ground look? Is it corroded? IF you’re Gen I is more than 10 years old then you may want to check this out. If there is any signs of corrosion on the inside of your Positive or Negative cables you will have trouble. Of course you might have to cut back on the outer sheathing to make sure. The inside of my cables were black and green.

Have you done the ground crimp upgrade/fix?

If you are not charging at 13.8 to 14.3 at 2500 plus then this is a sign of a potential problem.

I had a similar issue but I have a slightly modified Vmax that is no were near stock. But my issue ended up being related to a simple chassis ground issue. I replaced all my ground cables going to the frame, voltage regulator and battery. I went to a larger gage ground wire and made sure that my contact areas on my frame and engine were clean, clean, clean (NO Paint, NO grease, NO dirt). My bike went from charging 12.3 to charging 14.2 VDC.

If your bike is charging at 12.3 VDC then that’s not enough to charge your battery. When your cooling fan kicks ON in stop and go traffic for long periods of time your battery will eventually drain. Believe me.

If you want to talk more about this please feel free to contact me off-line. Let me know.

That's the best fix for ya!! rectifier behind the rear left peg.

Was the voltage you read off the stator ac/ or dc... ? I think it would be an ac voltage that fluctuated with rpm. Do you have a shop manual ? gives you all the tests for like diode check on regulator ect..
I've had intermittent issues with the rectifier. Easy enough to replace these thing in sequence.. Battery, Rectifier then stator if needed.!!

Later,
Mike D

i checked and replaced all affected cables, did the extra frame ground wire at the regulator itself, cleaned all ground contacts etc...I'm replacing the reg anyhow so I'll let you know how it goes. Thanks, Mike

The battery is also 1 month old....could be bad but totally doubt it as it checks ok after a charge and a load test.

One of our site sponsors has a pretty good deal on what you need..

Score!!

Before I replaced my harnesses/wires I replaced my old voltage regulator with a new slimmer FJR voltage regulator and Venture style Stator. Unfortunately neither fixed my problem. It sounds like your on the right path to fixing the problem.

If I'm thinking right, when the cooling fan kicks on it draws 4 amps. I would have to go through my notes to find out what the stock fuel pump draws. Its not very much at all. I'm currently running a aftermarket fuel pump that draws 4-5 amps at 40-42 PSI. When my fan kicks on it drops my voltage down to the 13 Volt range but it never dips below that as long as I don't let the bike sit and idle for a long period of time.

That unit is for a 85-95 Vmax. I believe the bike is a 96 (Digital Ignition) I would do some research before purchasing.