TOPIC:

On my KZ440, when starting up cold, with full choke on, it will struggle for a few seconds, then I'll hear a "pop" from the carb, and the revs go way up to about 4000. I'll then lower the choke level to bring the revs down. It will then struggle again, almost like it wants to die. So I pull the choke back to full again, and "pop" again. I go through a few cyles of that until it warms up enough to idle without choke. Once warm, it idles nicely at 1100 RPMs with the choke off.

What's going on in there, and is there anything I can do to fix it so that I can maintain a reasonable 2000 RPMs until warmed up?

It sounds like you have a pretty typical early 80's Kawasaki. Due to EPA regs Kawasaki jetted all the carbs of this era very lean so cold starting is always somewhat of a challenge.

That said there is one thing you might take a look at. I remember a TSB that Kawasaki put out on this model concerning the air filter. Under your seat you will find a rectangular plastic box held on by two phillips head screws grab the back of the box and gently try to lift it up. If it pulls away from the airbox at the bottom it is not installed correctly. There is a lip that must be fitted into the rear of the airbox before the screws are installed at the top in order for it to seal properly. This caused all kinds of problems back in the day, poor throttle response, blued pipes, poor starting etc.

Part #11012 which Kawasaki calls an airbox cap slides into part#11010 and then gets screwed down on top. I hope this makes sense.

Post edited by: The Gringo, at: 2007/01/03 08:51

Thanks, Gringo.

I remember reading about that TSB somewhere. To try to a better seal between the filter box and the airbox, I had put in some rubber-foam tape around the edges. I'll check to see if that has come off, or is leaking somewhere.

Other than that, would you suggest installing bigger jets? Which jet is being used on warm-up with the choke on? Would bumping that jet size up a notch help, do you think?

That'd be your pilot jet..your mixture could also be too lean, which means you'd have to adjust your mixture screw a little. Its sometimes covered by a little plug, which you'll need to remove to get at the screw.

What will be my expected results if I don't install the airbox cap and the rubber hose from the input side of the carb to the air box.

Can I remove the air box completly and if so how will the carbs react?

What will be my expected results if I don't install the airbox cap and the rubber hose from the input side of the carb to the air box.

Can I remove the air box completly and if so how will the carbs react?

If you don't filter it, you'll get a lot of air heading into the carbs.. you need something on there to slow it down, and make sure that something larger than a molecule doesn't get in.

That'd lean it out for sure..