I have an 01 Grizzly 600 I picked up a while back. It started to develope some idle issues.
AT first it was idling low. Had to keep the choke on for it to idle without stalling
It ran fine under throttle though.
So I adjusted the idle thumbwheel for a bit higher idle. Which seemed to work..for a short time.
However it ranges all over especially if you use the choke to start it....it's high...it's low...and so on.
Not sure what is causing this..again cannot get and maintain a reliable idel speed.
scott

 

I had a similar issue with my 00 Kodiak. Took it to my local shop since I'm not comfortable working on carbs. They cleaned the carb and replaced the choke mechanism. It was sticking. It now runs like it was new. No more idle issues.

 

yes, cleaning the carb could be the problem. The idle circuit is small, clean the pilot jet in the carb. Also look for air leaks from the air filter to the carb and from the carb to the engine. Mine had a crack in the boot going to the engine. Also had pilot jet gummed up, both did what you describe.

 

Sounds like it could also be a problem with the gasket or some other air leak.