I got a 2003 kodiak 450 yamaha, it will not idle all the sudden and the reverse light is flashing when it does run. above an idle it okay. I have cleaned the carb.

get a colortune tool.it shows how your firing.read instructions that come with,so simple to tune carb in with.sounds like pilot out of adjustment.could also have a leak in ur carb boot or head.take a torch without lighting open valve with motor running run torch around gaskets and front of carb boot listen for change in motor.if it gets higher rev uve found a leak.

Under seat

IS THE CARBURETOR AIR FILTER CLEAN?

its either the voltage regulator (most likely) or the stator. you'll need a service manual to check the stator output.

turn the idle down? choke could be stuck too.

Check your fuses.

Does this unit have disc or drum brakes?

http://www.imperialsupplies.com/pdf/A_FastenerTorqueCharts.pdf

probably dirt in sensor on front wheel

Sounds to me like you have a bad ground wire somewhere