fuel delivery

Hello all, reassembled my 1977 KZ650B1. But it still will not start. Fuel appears too be coming from the air box. Im not sure how it is getting to that point. I did not see any fuel leaking any where else. There is fuel in each of the float bowls. If anyone has any suggestions how or why this is happening, please enlighten me. I want to ride so badly I can taste it. Thanx for your time and efforts folks ... PEACE Larry

Did you wet check the float heights? (Using clear tube threaded into the fuel drains, when fuel turned on it should sit 2mm +/- below the top of the float bowl) Sounds like they might be off, letting too much fuel flow, which would for sure keep her from wanting to fire off. Do you have the overflow tubes hooked up on the carb bowls? If so those are probably routed under the airbox and you likely have fuel running out of the overflow.

If your fuel level is that high, you might want to sniff the oil and make sure you haven't fuel contaminated the oil. If it smells like gas, change it before starting the bike!!

No I did not check the float height, but I did run the over flow hoses under the airbox. Thanx for the help ... PEACE

lgj069 wrote:

No I did not check the float height, but I did run the over flow hoses under the airbox. Thanx for the help ... PEACE

Am thinking one or more overflow circuits is obstructed and allowing fuel to rise up into the carb throat where it flows to the airbox and to the combustion chamber.

When overflow circuit is functioning properly, the excess fuel getting past the float valve for whatever reason(s) will escape through the overflow without rising up into the carb throat.

The excess fuel is likely resulting from leaky float valve(s) and/or malfunction of float(s).

Good Fortune!

Hey Patton, thanx for the info. Things are starting too make sense too me now. Do you know how to identify mikuni carbs? The ones on my bike are not orignal, but I cannot seem to identify them positively. Ive been all over Ohio, the internet, and the phone trying to identify them. Thanx again for your time and efforts ... PEACE Larry

Post up a pic of the carbs, someone here will know what they are for sure.

Since there's fuel in the airbox, it might be a good idea to check the engine oil to make sure it isn't contaminated w fuel. No first hand experience with the phenomenon, but I guess you could check at the oil gauge site glass or remove the oil filler cap & sniff for gasoline.

I should have photos up today. Need too find the data cable for my camera.

I could not figure out how to send more than one photo at a time. Hope this helps.

It looks like the overflow nipples are capped.

They were but, when I installed the carbs I ran the hoses back near the swingarm.

lgj069 wrote:

...1977 KZ650B1

lgj069 wrote:

...mikuni carbs? The ones on my bike are not orignal, but I cannot seem to identify them positively....

Carbs on the 1977 KZ650B1 at hand resemble the 28mm Mikunis used on later Z1's. But am uncertain whether carb spacing on KZ650 would permit fitment of Z1 carb assembly.

Am thinking oem KZ650 carbs were 24mm, and would be over-carbed with 28mm.

Could measure inside diameter of carb throat at engine side to determine size of existing carbs.

Good Fortune!

Photo on right courtesy of Z1E.

[Click on image to enlarge view.]