Needing some assistance I have a 2005 Honda Rancher trx400 that is great, runs awesome, but seems to be having an issue with charging. Testing voltage when power is off is 12.5 volts. When running, throttled up about half way, the voltage remains at 12.5 volts. The reason I have tested this is because it seems that when I ride with my lights on, the bike will die within an hour. Can't restart with the starter, but have enough power to have lights on the display. I can pull start it, and let it idle for a while, then drive for a while further. If I have a full charge on the battery, it can sit for a month or better and still fire up. The question I have, is this an issue with my rectifier or my stator? Any assistance would be greatly appreciated.

 

It could be either. Most Honda charging problems are from the regulator, we have spares for all the models, and just fit a new one if the bike stops charging. If that doesn't cure it, I check that battery power is getting to the regulator by wiring a high wattage test lamp up across the red & black terminals of the plug that goes onto the regulator. The lamp must burn nice and bright. If the regulator and it's wiring are OK, I check the yellow wires for resistance, they should all be the same and not earthed. The 400 stator is particularly prone to burning out for some reason.

 

Thank you merryman. I'm digging into it more today. I am also wondering if there is a fuse between the regulator and the battery. I just found it odd that there appears to be absolutely no power coming from the regulator to the battery. No fluctuation in any way. I'm new to ATV's, but doing my own repairs on vehicles is old hat to me. I have the basics, but when it comes to specifics, I'm very green. I'm hoping that I can find a simple fix, as I may have LOTS of questions if replacing the stator.

 

There is a fuse on most models. However this cuts the power to everything else as well. Check the other way, that battery power gets to the regulator, as I indicated above. Don't use a voltmeter either. I found this the hard way, when I replaced a Honda 500 stator and it still didn't charge. It turned out that a crack in the insulation had let moisture into the live wire from reg to battery and about 1/8" had turned to green verdigris, 12v got through, but power didn't.