I have a 1986 Kawasaki bayou 300 I just put a new carb on and it ran ok with trouble idling. The problem is it won’t start back up when it’s up to temp or even a little warm. What is causing this? It has spark and compression and also is getting airflow. The fuel line is clear and getting to the carb. Also when I spray gas in the carb it back fires. The timing is set correctly too.

 

Is the plug black and sooty when you remove it after the engine has refused to restart? If so the carb is set too rich or the choke is stuck partly open.

Trigger coils can go bad too, they may be OK when cold but fail when hot. Any ignition part can do this but triggers are on the engine, so get hot from it. Also worth checking the voltage at the battery with engine running on KLF300s, as an overcharging regulator can feed too many volts into the ignitor module, causing it to pack in, then start to work again after it cools.

 

I checked spark again and found that it loses spark after getting it warm from riding it around for around 45 minutes. What would cause this? Is it the CDI box? Or is it the pulse coil? Also my Neutral safety switch went bad. Is there any way I can just by pass it?

 

If you earth the light green wire from neutral switch, it will by-pass the safety, but bring the neutral light permanently on. You could jump the black and black/yellow together on the secondary solenoid, not the main one with the two thick wires. However, if the switch is easy to get at, I would replace it. Easy to leave ignition on if there isn't a green telling you to turn it off and KLFs have a habit of missing neutral when you come out of reverse, so good to know if it is in neutral, or first.

Have you checked the charge rate? I had a KLF that would loose spark due to the voltage reg putting too many volts into the ignitor (they don't have a CDI). Usual suspect is the pulse coil though, only way to tell is to test it cold and then when the fault is on, and see if the voltage and resistance differs wildly. I had an Ozark that was fine until it had been running for 10-15 min, then would cut. Took me ages to catch it with my meter handy when the fault was on. Could also be ignitor or ignition coil, so test before throwing money at ignition components.