Problem: battery doesn't charge
cannot start after stall
when coming to a stop down a hill bike stalls even with 2500rpm idle

What I've Done: Hooked up a multi, at 2000rpm it read 14.2V for about a second then changed to 11.2V where it stayed. I rev it up (5000rpm) and it stays at that voltage.

The battery is 10.8V with bike off. Won't crank over of course.

Battery brand new. Worked fine when it was initially put in.

Solution: Since i'm new to motorcycles but not cars. I guess it would be the alternator if it were a car. Until I research and find there are more electrical components for the bike. I would like to know what you all think needs to be replaced?

The part I do not get is that the multi read 14.2V for an instant then it would go straight to 11.8 ? Could it be a regulator? I kept connecting and disconnecting the multi and it usually read 11.8 but sometimes it would flicker from 14.2.

This is my DD and i cannot afford a shop to repair it right now. So unless I can figure out what it is I might have to take it in for diagnosis!

Please Help!!!

Thanks.

 

I'm no genius with electronics but I'd be willing to be its the stator, or maybe the Regulator.

 

Well the bike wouldn't idle below 1500rpm bc it wasent producing enough voltage bc the regulator was toast. Replaced it and now it runs like a dream ... took all of 5 mins to change it

 

So the bike wouldn't run at all below 2500 rpm? I am having charging problems also but mine runs battery completely dead then the bike quits firing on mine. Anyone have idea about that one?

 

What wires would I check and what voltage would the stator put out with bike running. I haven't tested across battery yet

 

Yeah, I had this problem about 2 years ago. My problem was once the bike and regulator got hot, the charging system couldn't hold 12v at idle. I checked the stator and it was putting out the correct voltages and wasn't shorted. So I put a new regulator on (new style stock cbr one). About a month later, started having the same problem again. Checked stator, still doing what it should, so only other suspect was the regulator. I put a new style FH012AA (yamaha part number) regulator on mine a few weeks ago, and haven't had any problems with charging system yet. It uses a mosfet chipset, so it's way more efficient at converting A/C voltage to DC voltage withing wasting a lot of it to heat.

 

So that part works better? I have to fix my bike. I do whatever it takes. I was thinking regulator anyways

 

Yeah, I haven't had any problems with the new 07+ regulator. Runs way better. The old style just wastes too much power off into heat. Make sure your stator is with-in spec for voltages and no shorts, then do new battery (if you don't have one) and the upgraded R/R.