Need some help. My 02 650 won,t start unless the choke is on full and I have to pump the throttle. Have tried starting differant ways and nothing else works. When throttle is relaxed the 650 dies. Have changed gas, and spark plugs. Some times at half throttle the engine back fires thru the carbs.[Note I had the air cleaner off trying to squirt some carb cleaner in it when it backfired.] This machine did sit for 3 months without starting and I am sure I ran the gas out of the carbs. Any ideas??

 

did you try fooling around with the air mixture yet?

 

No,I did'nt try the air mixture screw. Don't even know where air screw is as I'm not a mechanic.

 

if you look on the right side of the machine (when seated on it) look at the carbs on the bottom of them there is one screw per carb on mine they had a blueish mark on them. take and warm the machine up to operateing temp. and turn the rear screw in all the way then back it out till the engine idles smoothly keep turning it till it idles rough again then turn it back 1/2 turn (im not sure how far you turn it back) then do the same for the front worked wonders for me

 

Well have you tried turning up the idle, it is a plastic **** on the right hand side of the bike down by the carbs. I know I need to adjust mine every once in a while. And choking it when the engine is cold is normal.