hi there im new to this site but i also own a yamaha warrior 350. if none of the above solutions have fixed it try having a look at the clutch lever housing theres two electrical switches on there cant remember exactly what the precise usses are of them. but i know from experience with mine that if you have the parking brake on or even the slightest bit on it affects the throttle response like a built in restrictor to help stop you driving off with your handbarke on if your not using parking break seriousley just tighten bolt or even unplug the switch i have done it with mine and has made no difference at all still runs sweet as a nut lol hope this helps. and what uv said about getting rid dont as the warrior is one of the toughest engines yamaha did and i love mine and will never let go cheers AJ