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Bain
03-27-2015, 03:59 PM
Hi guys. I apologize for the long post, but want to explain my issue in detail.

I've got a 2003 400ex that I've been having issues with. Over the winter I rebuilt the entire engine, top and bottom, and also stripped the frame down to metal and powder coated everything, also new black plastics. Basically restored the whole thing. Runs great and looks great!!

I put a new battery in it that was fully charged. Everything seemed fine. After sitting for a few days, the battery was completely dead. After putting it on the charger, the charger kept saying there was a fault... I tried a different charger but same thing, fault and it won't charge. Thought it was a problem with the battery so I replaced it with a brand new one, but same thing. A few days later, dead battery that won't charge.

Im great with mechanical issues, but am somewhat new to electrical diagnosis... So, not knowing much about it, I bought a new stator off of ebay. Installed it and it ran but when I unhook the battery, there is no power to any of the lights or neutral light. The engine continues to run however. SO, I started reading about it and thought it was the regulator/rectifier. So I bought a new one off of ebay as well. Installed it, and it didn't help. So I started poking around and testing. I was not getting any voltage to the battery with the engine running. Swapped the old stator and reg/rectifier back in and now I am getting about 3 volts to the battery with the engine running. Now the lights DO work after unhooking the battery, however, they are bright at idle. If I rev the engine at all they dim down to almost nothing...Very confusing!! I have a new battery sitting on the bench waiting to go in, but Im afraid if I do install it the issue will kill the battery again. So my question is, how do I find the problem?? First off, the issue of draining/killing the battery. Secondly, the lack of voltage issue. Where do I start! Do NOT want to bring it to any stealership.... There are some bright minds here that I know can help!!!

THANKS!

Stickman400
03-27-2015, 05:10 PM
Did you grind the powder coat off your frame where the coil sits on the frame? It needs to be grounded straight to metal on both of the prongs.

Bain
03-27-2015, 05:17 PM
Did you grind the powder coat off your frame where the coil sits on the frame? It needs to be grounded straight to metal on both of the prongs.

Yeah did that. Coil is grounded fine. Bike runs good. Issue is with the charging system.

Stickman400
03-27-2015, 05:26 PM
Sounds like a grounding issue to me. I hate wiring aswell so I'm not much help here. Only thing I can think of is checking grounds and look for bare or broken wires. Sounds like you have replaced anything that might have been the problem.

ride red 14
03-27-2015, 06:50 PM
X2 on the ground. Your battery grounds to your subframe. Grind the powder under where the ground wire bolts on it. Then grind the powder off where the frame and subframe bolt together. Then grind the powder where a motor mount bolts up. Then you have a ground on everything and go from there. Powdercoat sometimes won't let things ground good.

Bain
03-27-2015, 08:17 PM
X2 on the ground. Your battery grounds to your subframe. Grind the powder under where the ground wire bolts on it. Then grind the powder off where the frame and subframe bolt together. Then grind the powder where a motor mount bolts up. Then you have a ground on everything and go from there. Powdercoat sometimes won't let things ground good.

I'll check it out. Would a bad ground really cause a drop in voltage while revving?? I just checked the stator output again. It was putting out around 16v AC to the yellow and pink wires... I think thats normal?? Can anyone verify? That would rule out the stator as a problem correct? I've ohmed it out and all is normal according to spec.

Bain
03-30-2015, 01:50 PM
anyone else have any input?