Weird Problem with 1984 ZN700

I have cleaned, tuned and re-installed the carbs. Using my portable fuel tank, it starts easy, runs great, and idles smooth. Throttle response is great. Now for the weird part...when I install the fuel tank, it won't stay running, and throttle response is bad. The petcock is operating properly and fuel flow is good. Now what? could it be the vaccuum line going to the emissions canister? I am at a loss here...:dry:

Post edited by: ten6, at: 2007/08/11 00:41

Is it possible that the tank is pressing on a wire or something that is loose? You might try this; hook up your portable tank but put the regular tank on the bike and see if the engine runs properly. This might show it the tank itself, rather than the fuel supply, is creating a problem. Ed

Is the petcock vacuum operated? Try the prime position.

Does the problem exhibit as soon as you mount the tank? Or after a few minutes of running? Try putting the tank on the bike but keep the fill cap open. If the problem goes away your vent is plugged.

KZCSI

There was a vaccuum port under the tank behind the sending unit that connected directly to the carbs. I plugged it on the tank and on the vaccuum hose and all is right with the world.