Bad Battery Or?

[torch]

With the engine running, measure the voltage between each pairing of the white wires on the harness side.

Actually, this is another good place to use a clamp-on ammeter -- this time with the connectors plugged in and looking for AC current, of course.

Attached is a nice article with pictures explaining the use of an oscilloscope to diagnose the charging system better than I did.

 

[RedRiderMN]

@K-Flyer

When I had a set of Motolites on my BMW, I replaced the incandescent bulbs with some LED bulbs. This significantly reduced the drain
on the electrical system.

https://motolight.com/product/super-bright-led-motolights/



Their website does NOT list the wattage for the LED bulbs, however.

 

[Rocnsanman]

Bike has over 65k miles. Problem just appeared a few weeks ago. I'm also surprised that battery discharges at 13.8. I'll try some of the other suggestions. But winter is coming and I think I will ride without the moto lights until I can get to checking it out. Wish I could find a mechanic in the area that I could trust. I have too many problems with back and knees to do much myself. Picture is of me at least 25 years ago. I've worn out somewhat since then.

Haven't we all ........

 

[K_Flyer]

Like a bad penny, I keep coming back!

To update this sad story, I talked to a guy at the local motorcycle repair shop who came to the same conclusion we all have, that it was the stator, perhaps along with a bum regulator. He had lots of good reviews, some from people I know, so I bought a new stator, regulator and related gaskets. The parts are here so I took my bike in this morning. He called me after an hour or so and said it was too big a job for him to tackle and I should come and get my bike and parts! Seems his experience is with Harleys, dirt bikes and quads. He said to go to a dealer, something I already tried. (See a few posts above). So now I have the parts and the additional challenge to find a Yamaha repair shop who is willing to just replace the stator and regulator without charging a lot to "diagnose the problem since we have already done that. Any suggestions for a good Yamaha repair shop near Sacramento?

 

[harper]

Ask SacramentoMike where he gets his work done. It may not be a Yamaha dealer.

Charles ended up replacing a stator in THIS THREAD.