[pastorjason]

I've had my kz440 for years. I rebuilt the engine about 10 years ago. It has sat for the last 4 years. I put a new coil on it and a beautiful set of carbs I got off ebay. Cleaned all the rust out of the tank.
It starts great, but once it warms up and I take off the choke, the idle is erratic. It runs strong through the gears, but when I take off the gas, it will either idle ok, idle low and die, or rev to 3-4,000 rpms.

The vacuum gauge on either carb at idle is all over the place. Steadies at about 3,000 rpms.

Anyone have any ideas?

 

[MFolks]

Check your mechanical ignition advancer. On the larger 4's, it's under a CD sized cover on the right side of the engine The advancer acts to retard/advance the ignition by using springs and weights.

Make note of how it's assembled, as it can be installed 180 out, light oil like sewing machine oil or 3-in-one on the moving areas and pivot points should work.

Have you checked for a vacuum leak? to do this, start up the engine, and then spray carb cleaner around the rubber ducting and carb manifolds.

If the rpm goes up, you've got a leak. Also check the rubber plugs on the carb vacuum ports as the rubber can crack from sunlight/ozone exposure.

The website:THE KAWASAKI TWIN OWNERS FORUM :: Index will help too.

 

[StarGate]

Sounds like an air/vacuum leak. The 440's have been reported to have bad idle if the air filter isn't seated in the airbox correctly and the airbox in tact. It could also be a cracked vacuum line or leaking around the intake manifolds if they are cracked or the carbs aren't seated in them correctly and clamped tight.