Carburetor/Fuel pump question, non-Z

Well I have to apologize first off because this is a non-KZ bike. I think it has KZ applications, though (read on).

Anyhow, the bike is a stock 1989 ZX1000. The stock setup is very similar to the Z's, 4 CV carburetors. There is a twist though, the carburetors are fed with an electric fuel pump. The fuel pump pumps gas into the carburetors until the float valves close up causing pressure in the fuel lines to rise. There is a diaphragm inside the fuel pump that "senses" this pressure change and shuts off fuel supply when the pressure is too high.

Here is the chain of events, stick with me, the order of events is important:
1.) Cleaned carbs
2.) Turned on fuel pump
3.) Carbs/engine flooded with raw (liquid dribble) gas
4.) I cleaned up the mess
5.) Turned on fuel pump again
6.) Bike ran fine for about 100 miles
7.) ... After which when fuel pump was turned on carbs flooded again.
8.) Replaced float valve/needles
9.) Set fuel height
10.) Turned on fuel pump
11.) Carbs/engine flooded with raw (liquid dribble) gas
12.) Replaced fuel pump
13.) Turned on new fuel pump
14.) Carbs/engine still flooded with raw gas
15.) I cleaned up the mess
16.) Turned on fuel pump again
17.) Bike ran fine on the stand
18.) After 2 minutes the carbs/engine flooded with raw gas.

You made it! So basically the fuel pump (new and old) sporadically "freaks out" and overfills the carbs. I've done everything I could think of to prevent this from happening, but it still happens.

BTW - it seems like all of these electric-fuel pump carbs don't have the "overflow" safety system that our Z's do, can this possibly be correct?

BTW these carbs make 150HP on my bike and you can find them everywhere on the net for 100 bucks or so. I think the carb spacing might be correct for the KZ1000+ but I'm going to check.

I'm not too familiar with pump-fed carbs, but here's a thought; Does the carbuetor have a float height adjustment you might need to make?

PS I think you'll find that your bike makes xxxhp with those carbs and not vice versa

Yes, the float level is adjustable. Indeed, I've adjusted it once to no avail.

I've been considering the chain of events and I realized that I haven't readjusted the fuel height after the last time that the carbs overflowed. So I *think* that high system pressure (something WG told me to look for) from my old defective pump has caused the fuel height to skyrocket bending the float tangs in the process. It seems like a bizarre occurrence to me, but it's possible.

Also, carb spacing is tighter than a KZ650, so I doubt it has a direct application in the KZ world.

Post edited by: newbikekiller, at: 2008/01/07 14:38