Well after changing the fluids and checking everything out on my 85 Quad Racer I noticed my headlight isn't working.
I checked and the bulb is good. Any suggestions on where to start looking for the problem?

 

trace the yellow wire with stripe coming from the light all the way to the flywheel cover, get down there check your source coils under flywheel.

 

Okay, I had to take the fenders, tank etc. off- I've started looking for any loose wires or connectors. Haven't found anything obvious yet. I left my manual at work- could the CDI unit or regulator/rectifier have anything to do with it?

 

test the stator. the yellow/red wire should have about 1 ohm

 

Well the good news is that I finally got the light working. Apparently the previous owner had for some reason snipped the 2 wires (R/Y & Gr). The manual calls for those 2 wires coming from a lighting switch that my quad (85 LT250R) doesn't have, just the dimmer and engine stop switch. I was reading an article about 3 years old and the guy said he had to connect the 2 "extra" wires together and his light worked. So I thought what the hell- just hoping I wouldn't fry something??? And the light came on and worked just fine- Hi & Low beam!
Hopefully it will continue working....
Thanks for all your input and help.