instantly starts, holds idle for while, starts dying, can't recover with throttl

I've never been this snakebit on a bike. It will start just fine, holds idle for a minute or two, then starts to die down, and can't even be kept running when I twist the throttle. I tried sticking my finger in the intake of one carb and lifting the needle and it responds positively to that. I have tried rebuilding the carbs, replacing all the gaskets (some more than once), the boots between the head and carbs are in tact. I'm at a loss.

Any helpful information is much appreciated.

How is your fuel flow to the carbs?

well when I loosen the drain screws the gas flows pretty well, so I suppose it's good..??

Are the coils getting too hot?
Steve

mnrenfro wrote: well when I loosen the drain screws the gas flows pretty well, so I suppose it's good..??

You may only be getting fuel from the bowls. Try taking your hose off at the carburetor and check flow with the petcock full open.

that I don't know. Was that a problem on the KZ400 model?

thanks I'll try that.

The reason I suggested it was because it sounds like the bike is starving for fuel...just like when the petcock is shut off while the engine is still running.

Fuel cap breather hole blocked?

I bet it will only run with the choke on?