My friends 300 Sportsman had the battery terminals reversed, After that his lights ( brightness ) goes up and down. I haven't checked anything yet. It will start by pulling on the starter rope. I am looking for advice on what to check out first. Any advice is appreciated. thanks grm

 

Possible shorted battery with terminals reversed! ALSO lights will flicker if battery wont hold voltage,charging from reg/rectifier has to go somewhere if battery bad,lights are first to take the excess voltage and usually will burn out if problem not fixed. Good luck

 

Will the battery hold a charge?
If so........Chech the battery with a volt-meter and should get near 12 volts
Then start Quad up .....Check again while running......Should be higher......13-14 volts....
Don't know if that year has a separte Reg/Rectifer........I had one go in my old Yamaha Exciter Sled and the headlight would go bright and blow out after using for a short time.......Caper.....

 

Thanks for the reply, What procedure do you do to check to see if the rectifier or regulator is bad? The battery has been changed twice so I imagine that is not the problem. Thanks again. grm

 

Also make sure the connections are nice and tight and the battery from when he changed them over. A loose ground connection will cause this.