I have a '94 zx9r. It idles well with the choke on and the throttle off, whenI twist the throttle, the engine wants to quit. I have changed the plugs and wires. The fuel filter is new. Could this be a fuel pumpor a vacume issue?

Any help would be appreciated...

 

This is in no way meant to insult your intelligence, but do you always leave the choke on? The way you posted it seems like you leave the choke on all the time. Only use the choke to 'cold' start your bike and leave it on for like 30 seconds, then turn it off and let the bike idle some more to warm up.

 

LOL, I could see how you could read it that way. No, It is just the only way I can keep the thing running while I have this fuel issue. I also posted this same problem under ZX-9R forum here. You can see what some of the guys came up with for possible solutions...Thanks though..