Ok towards the end of last season i started having a charging problem. I could charge the battery up and run for about 2 days before it would go dead. Fired it up today because its right a 60 out side and rode it around a little bit. I brought it home and but a volt meter on the battery. It's sitting right around 12.80 at idle and slowly going down. If i rev it up to about 4g it will shoot up to right at 13.0. If i turn the bike off the battery also will jump up to right at 13.0. Any ideas?

 

So what are you worried about? that the battery isn't holding a charge or because the reading is at 13.0?

 

miss post

 

Well its going dead every 2 or so days so that what i'm concerned about. Its a new battery, put it in right before the end of the season. Took it and had it tested and its good, did that today. What would be causing it to slowly run down? If the voltage reg is going bad will that do it?

 

My bike was doing the same thing but my battery is old. Did you do the poor mans alternator test? disconnect the negative cable while the bike is running. I'm thinking if the alternator has problems then your bike is running off the battery. You can check the regulator I believe by testing it's voltage or ohms with a voltmeter when the bike is off but I'm not sure about the specs so I would check the manual.

 

I'm sorry , but if you do the "poor mans test" you might as well just go buy the regulator/rectifier. Pulling the the negative cable off will blow the shyte out of the diodes on the rectifier...even a new one.

 

ok, so whats the proper way to test the reg? We got a beautiful week of 60 plus temps and no rain, wanna get this thing going.

 

Here are a couple of pics from the service manual. Hopefully they are clear enough to read.

 

Here's the end-all, be-all charging system thread:

https://cbrforum.com/forum/general-tech-stickies-106/how-diagnose-charging-system-51691/

I've referenced it a ton of times, and can't think of anything that isn't answered in there.

Either way, if you're killing your battery every 2 days, I'll guarantee that battery is trashed, just from doing that to it. Most motorcycle batteries, especially cheap ones, can't handle more than a couple "kills" before they won't ever hold a charge properly again. If you find that your charging system is bad, replace your R\R and battery. If your charging system is good, replace the battery.

 

why would it blow the regulator/rectifier diodes if it's pulling current from the battery instead of the charging system?