Weird stuff going on with my bayou 300

[Jeff Comstock]

So it's been a while since I was on here begging for knowledge but....here I am again, like a bad penny.

So my 300 bayou was fine and I drive it close to 30 miles a day ( no joke, no license). I pulled over to light a cigar and drove 100 ft and started down a dip in the dirt road and it acted like it was out of gas (just filled the tank) but then when I tapped the brakes it started running fine.

Now it'll start but runs rough unless I turn on the headlights and brake light them it'll even out and at first it'll skip and backfire almost them it'll run fine untill it goes to idle them repeat above. If I sh** off the headlights it wants to die. My boss has the same 300 so I swapped battery and cdi and regulator with his and still the same jazz. Could it be the coil? Don't they do like old cars and just die? Also went I throw my voltmeter on the battery while it's running it sits at 9.87-.99 like it's not charging, did that even with different battery, reg., Cdi. Checked the grounds, all good. It's always been a rule that if a battery has only 9 volts then turning on the lights drains power and it runs worse. I'm confused like I just saw a churchmouse kick a barn cats butt

[davefrombc]

That's a strange one indeed. Does the battery read the full 12v + with the motor off and just that lower reading  when it is running?   Turning lights or  other accessories on with that low a voltage  should kill it rather than  make it  run better .. I'm  wondering if  maybe there  is a bad diode allowing AC to  cause false readings on your voltmeter.  What  are the readings with  everything turned off , when   ignition on   but nothing running and   is it always that low a reading with the motor running?  Can't help  more than to  just suggest  those checks  to help you diagnose  or someone more knowledgeable than me  to  use to  help  you diagnose it further .

[Jeff Comstock]

Yeah Dave, it's always that low but, when I check my bosses 300 with the same meter it reads 12.35-79 with it running, even swapped coils this morning before work and still no joy

[Dave Randolph]

I would check all your charging system connections first. make sure they are making good connections. With the voltage that low i would say its the stator but it may be that both of them regulators are bad. I had one that past every test i could find to do on it. one test was just barely out of spec and it ran terrible. if you do test on the regulator, follow then exactly. its easy to get that one wrong.

[Savage3]

Regulator is probably bad. I'd replace before it takes out the stator. First use multimeter and verify rectifier is bad and ensure it's not a short to ground. Rectifier should be pushing over 14 to the battery. 

[Jeff Comstock]

Thanks, you were close. I found the white wire that goes to the battery and has the fuse in line had gotten pinched somehow and only had three strands left. Patched it and now everything's fine. Mech from New Zealand gave me the clue when he mentioned turning on the lights to get a few more rpms to a guy who posted about a similar problem with his 400

[Savage3]

Great news man! Glad ya got it!