My 300ex won't run unless hooked to jumper cables or to a battery charger. When I try to rev it up it gets quieter instead of louder, is the stator bad? Could a CDI cause this? Could something with the ignition cause this? The neutral light only comes on when hooked to a power source and goes off as soon as the power source is connected. After I disconnect it from a power source it'll run for a few minutes then die. It'll also pull start but pushing the gas nothing happens, the choke isn't on and the gas isn't on reserve. My friend thinks it may be a stator because after I charged the battery and went to ride it the other day the battery was drained again. Any help would be appreciated as I'm lost and don't know where to start

 

Battery is flat. Charge it up then put one battery lead back on and an ammeter between the battery and the other battery lead, there should be no discharge with everything switched off. If there is more than 0.01amp discharge, disconnect the voltage regulator and see if the fault goes away. If it does, get a new voltage regulator. If the ammeter shows OK, re-connect the battery and start up. Put a voltmeter across the battery terminals, the voltage should be over 13v and move about as you rev up, peaking at 14.5v if the battery is charged. Switch off and the voltage should instantly drop, if it doesn't, the bike is not charging, remove the plug on the voltage regulator and check for power between green and red wires. I use an incandescent test lamp, a bright light indicates plenty of watts, a dim, or no light shows a broken or corroded wire between battery and regulator, this includes earths. If they check out OK, test resistance between each of the yellow wires at the regulator plug, if there are 3 of them, resistance should be equal more or less, and no yellow should be earthed. If you have only two yellows, things are a bit more difficult to test. If all the wires to the regulator test out OK, again it is probably a faulty regulator, get a new one.

 

Could the stator still cause this? Or does this just sound like a voltage regulator?

 

Could the stator still cause this? Or does this just sound like a voltage regulator?

 

As I wrote above, if the bike tests out that it isn't charging, do the tests on the voltage regulator leads. For a three wire alternator, I outlined the alternator tests above. " test resistance between each of the yellow wires at the regulator plug, if there are 3 of them, resistance should be equal more or less, and no yellow should be earthed."