Just bought a used 09 750 axi had same problems. Hard to start, wouldn't idle. Stalled as soon as I backed off the throttle. Finally pulled injector out. Have a container ready, to catch the gas. It,s under pressure. Pull the injector, use your thumb to block the gas or have a buddy catch it for you in a container. Blow it out with a compressor back & forth several times. Put injector back in & test. I was so happy! It worked for me.