I WAS RIDING THIS THING WHEN IT STARTED TO BREAK UP THEN JUST DIED. I CLEANED THE CARB, AND IT WOULD NOW BARELY IDLE, BUT DIES WHEN THROTTLE IS APPLIED. I CHANGED PLUG, CDI BOX, CARB, .SPARK LOOKS GOOD. I DID A COMPRESSION TEST, AND CHECKED THE VALVE TIMING AND CLEARANCE. I AM READY TO BEAT IT TO SCRAP WITH SLEDGEHAMMER. ANY IDEAS BESIDES TAKING IT TO SHOP 2HRS AWAY.

 

i have an AC 400 with the same sounding problem. its a diffirent year, 1999, with the previous model engine. but i had the same problem. for me it was two problems.

the first was the float needle inside the carnb was clogged, so if i gave it throttel it died. got that fixed just to find out problem #2

if was running lean for such a long time without me noticeing that it burn and bent the exhaust valve. so now it will only run for 20 mins max before the exhaust valve heats up and distorts, siezeing the engine.

sorry i cant be more help, but it might be worth a shot to check your valves for any dammage

 

THANKS, I WILL CHECK THAT.

 

You need to remove both jets and the float needle/seat and clean well. I think you have a plugged jet still.

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