Just got done changing my Grandfather's Bayou 250's oil, gear lube, filter, and plugs, as well as cleaning and oiling the air filter element.

However, it's still running rough and backfiring/popping when letting off the gas.

To be truthful, the carb has never seemed to be quite right. The dealer in Chattanooga TN is useless, so we are on our own (example, we were told adjusting the valves took too long so they quote "don't even fool with that". Great reps for Kawi, right?).

Anyhow, do you guys have any recommendations? The gas is fresh, the plug is new, etc. It just runs rough, idles poorly and cuts off after a couple minutes.

 

Before you make any adjustment/changes, first diagnose properly. Run your quad at 1/2+ throttle for 3~5 minutes and read the plug which should be new before testing. Determine whether it looks too lean or rich. Go from there.