I suspect the stator is bad in my sons atv. I have replace the battery and charged it. It worked fine for a day and then the battery was dead again. Does anyone know how I can check the stator and confirm it bad? Are there other things I need to check also? Thanks.

 

This is easy...

The procedure for checking whether your charging system is working is the same for all quads (and your car and truck too...):

Start up the quad with the headlights off. Rev up the engine to a medium fast speed. Measure the DC voltage right on the battery terminals while the engine is rev'ed up. You should measure 13.5 to 14.5 volts DC. If you do your charging system is working.

If you don't then the culprits are:

1) Bad voltage regulator
2) Bad Stator
3) Bad Battery
4) Wiring errors in this area.

 

I'll give that a try. I seem to remember there was a way to check the resistance between a couple of wires. Thanks.

 

You can check the voltage from the stator directly to see if it is outputting anything. Unhook the harness from your stator and set your multimeter to AC voltage. Rev the quad up to around 4000 RPM and see what you have. I am not sure the specific voltage on the vipers though but that will tell you if the stator is doing anything.

Make sure you are set on AC voltage for this test, the stator outputs in AC, the regulator/rectifier converts that to DC and regulates the amount of voltage getting sent back to the battery.

I have a service manual on the Sierra DLX90, it's similar to the viper but it doesn't say anything about testing the charging system.

 

I measured across the battery terminals and I have ~12.2V at idle and 13.2 is max at a high rpm. I compared it to my daughter's Eton 90 which is at 12.8V at idle and 13.8V max at high rpm. I think this stator is weak and needs to be replaced.

 

I could be a bad voltage regulator also.

I've never measured an eton stator AC output voltage, so I can't tell you what is normal or not. Have you tried emailing www.anythingATV.com through their web site? They have a tech support area, maybe they will respond.

Do your two eton quads use the same regulator? Maybe you can swap them briefly to see if the problem moves from one quad to the other.