I have a 1998 450 Foreman ES. I was having a real tough time shifting, and read on here that the ES system is a battery hog. Since I've only owned the machine a week, I figured getting a new battery in it wouldn't hurt, since who knows how the previous owner treated it. I bought a battery, charged it all night, then put it in Saturday morning. That fixed the shifting problems right away, except for reverse. Turns out there is a safety switch in the left hand break that must connect to engage reverse, and the switch was bad. So for now I just bypassed it, and now everything shifts fine.

The only problem is by night, after riding all day long with friends, it wasn't shifting again and the display and headlight were dimming quickly. I barely got it home to the garage before the battery was toast. I recharged it during the night, and put it back in Sunday morning and everything worked out fine. But again by the end of the day the battery was drained.

What part on an ATV charges the battery as you are driving. Apparently whatever it is does not work on mine, or a wire is loose or something. Thanks for your help.

 

The stator, which is like an alternator, provides the a/c for the quad. Then the rectifier/regulator does the converting to d/c.
If you have a voltmeter, hook it up to the battery, and read the static charge. With the key off, and all electrics off...the volts should be around 12.6. Then go key on, and start the motor, leaving the voltmeter hooked up. At idle the volts may be a bit lower than the static charge, but if you slowly increase the revs, the volts should come up. And by the time the motor is doing about 4000 rpm, the voltage should be at least 14. volts.
If this isnt the case, then something is wrong with the charging system.
Check the connections at the battery, they should be shiney and tight, where the metal contacts.
Let us know what you find.

 

I hooked up a voltometer last weekend. It was reading around 12.4 - 12.6 with the engine off. Then I started it up, and reved it and it was still 12.4 - 12.6. So I started checking all the connections I could around the battery and all seemed fine, all the fuses are working. I don't have a service manual so I didn't dig any deeper. I ordered a manual, so once I get that I'll see what I find from there. As a added headache, it looks like the previous owner did a little rewiring on his own, so on top of me trying to learn how things should be working, I need to figure out what he was trying to do. There are wires spliced together at random points that don't go to anything, some things have 2 or 3 wires going to the same place, and there's tons of electrical tape on everything. Hopefully the service manual will help me clear things up.

 

I performed the troubleshooting section in my service manual. It pointed towards the regulator/rectifier. I ordered one on E-bay and put it in last night. Looks like everything is working now and charging correctly. I'm happy cause it looks like the alternator would have been a pain to change compared to the regulator.