84 VF1000 F Electrical problem

I am having some trouble with the electrical sytem on my 84 vf1000f interceptor. It keeps killing my battery. I recently bought a new 16AH battery and changed it for about 16 hrs. with a 1 amp charger. I put the battery on the bike and it started right up. I rode for about 45min then turned the bike off. Then tried to start it up again and it wouldn't turn over.

I have checked the charging system and it seems fine. When charged the battery had 12.8 Volts across the terminals. With the battery on the bike and the engine running it read around 13.5 Volts. Is it possible that I have a short some where that is draining the battery. If so how would I check for one.

thanks

 

sound like it could be a R/R to me. Recheck the charging system after you have run it for a while when its good and hot. sometimes that is the only time it shows up.

 

Here's a site with a great fault finding chart for this type of problem:

http://www.electrosport.com/Images/fault_finding.pdf

 

Yep, that sounds like it's got something to do with the regulator/rectifier. You mention that it's got 13.5V when running. At what rpm? What is the voltage at various rpm's? These are key things to know because motorcycles do not charge at idle like cars. Also unlike cars they do not maintain a constant voltage - as the rpm's increase so does the voltage (to a point).

 

I took your advise Jaymz. After I had run the bike for 30 min the voltage across the battery was only about 12.3 volts throughout the lower rpm range (1000 to 6000). So I guess it's probly the R/R. Even when I tested the voltage with the engine cold 13.8 was the most volts I got no matter what rpm I was at. I read about 13.3V at idle (1000) and about 13.8 at about 6000.
Thanks for the help guys. Is there any way to test the R/R before I go out and buy a new one.

 

I think you DID just test the regulator/rectifier!