I have a 2009 yz450f works awesome but when driving and pull in clutch leaver it stalls or if u r just sitting and let go of the throttle it stalls it wont idle i already cranked the idle screw up..any idea?

are you refering to the clutch fork that connects to the other end of the clutch cable, you will have to drop the gear box as this fork sits over the clutch pressure plate ,and pushes the thrust bearing against the pressure plate tynes so disengages the drive from engine to gearbox, while you've got the box out check the condition of the clutch parts ie thrust bearing,pressure plate spring's,friction plate condition

cable clutch , too much free play on leaver, adjust so 2mm gap when pulling clutch free play ! hydralic clutch , may need bleeding or free play between actuator needs adjusting , or there could be a problem with the clutch it self !

It needs to be adjusted.

you can ride the cluthch on a bike un like a car you wont hurt it its oil lubricated constantly, sitting on the bike pull the clutch in with your left hand and click the left foot lever down in to 1st, then learn how to click it back up 1 half movement in to neutral. the neutral light will come on sfter the bike enters neutral. in first gear give the throttle on the right hand a squeeze and pull the clutch in with your left hand put foot gear selector down in to 1 st and begin to release clutch slowly. hold on as bike will engage may be jerky balance yourself! when you get moving stop! by pulling the clutch in and the hand brake as you close the throttle to stop! practice your take off many times some where safe! when you get your balance in 1st gear pick up speed and begin shifting the foot gear selector up in to 2nd gear and practice closing the throttle and breaking to a safe stop. gears are generslly 1st down 1 click 2345 and6th all up from there and neutral is 1 half a click up from 1st between 2nd gear. And dont put it in gear with the kick stand down t may stall on you

hope this helps

pull left leaver (clutch) foot down one on left prody thing (gear shifter) keep clutch in bit on throttle so it revs up then let clutch out slowly until it hits bitting point rev abit more and let clutch full out it will accellerate once done let off revs pull clutch gear shifter up fully release clutch and hit revs and when ur on the road it will be easily done and letting clutch out and revving will become simunatiosly

to slip clutch then rev high and let clutch out smooth and excact to bitting point and keep it there

With out pulling in you clutch I can't tell you if it is a normal pull or not. You can buy an easy pull ball and ramp for your clutch, or start working out your grip with a tennis ball.

sounds to me like your friction plates in your clutch assy. are worn down to much.