Just finished putting my second new carb on this bad boy. The first carb was a brand new cheap Chinese carb on which i put the OEM brass and the other carb (on now) is a brand new OEM carb from the dealer. Im having the same issue with both carbs. The issue is at normal idle speed when i push the throttle the bike wants to bog down and die. If I prep the throttle by lightly pushing it a couple times it will reach high enough rpms that i get my throttle response back and everything is normal until the bike reaches idle again. The bike idles and runs fine otherwise. If i set the idle a little higher (just above the shift grinding threshold) the throttle response is normal but you cannot shift the bike because the idle is a bit too high. I've tried adjusting the pilot screw between 1.5 to 2.5 turns. All hoses and vacuum lines are fully connected and the air filter and air box lid are snug and clean.

 

I am having the same issue with a '02 300 Prairie. Complete top end rebuild with good compression (100-110ish), tired stock and new carb, tired different timing selections, tired every adjustment new carb, tried high octane gas, Same issue before and after all of the above. Items above have improved but not solved. Getting the bike real nice and hot helps, but does not solve. I have to say I am stumped on this one and I've rebuilt and fixed a bunch of bikes. I would be interested if anyone else has figure this out. I have a feeling it's something common to Kawa's and simple...The only thing I have not ruled out is a worn out timing chain which looks like a complete tear down to do and would probably scrap the bike instead.

 

Believe it or not but I believe we fixed this with a new ignition coil. The original coil I bought was a cheap Chinese part, replaced it with OEM and bam, running like new.

 

Ok new (used) OEM ignition coil, same issue but seems to be a little better. I think your on to something and going to run a volt meter on it and work backwards to volt regular and stator.