Starting a rusty '82 KZ750

Either a float needle isn't sealing or if the carb bowls use an overflow tube, one or more of the tubes is cracked. I mention this second possibility because I've seen it several times on the 750 style Keihin carbs.

Thanks Nesism. I'll pull the bowls and take a closer look. Can I use the aux fuel tank if the carbs are working properly or do you think they exacerbate the issue?

A remote tank is no issue. Just don't hang it way above the carbs because the tank height determines how much pressure is in the feed line.

Use the clear tube test to identify which carb is leaking.
Steve

Tvag06 wrote: Hey folks. It's springtime in New England and I'm happy to say I got the bike running last night. It was idling pretty damn good and I was optimistic I would be on the road in no time but... then I looked at the floor and saw the gas puddle. Sadly the gas was draining out of the airbox which has me concerned about oil contamination as well (but that's a problem for another day). During this test, I was using an auxiliary tank I made to fuel the bike. After some inspection I realized this bike uses a vacuum fuel delivery system. So my gravity aux fuel delivery tank is most likely part of the problem. I would have assumed that the float valves in the carbs would have mitigated the excess fuel by shutting off the flow of gas as is their purpose. My question is this, could the flow of gas from this gravity feed be too overwhelming for the needle valves to cut the fuel off? I'm going to use the tank and petcock for all future engine calibration but was hoping to avoid having to pull the carbs again (they have been fully rebuilt).

My hearing is poor but my eyes are ok so you don't need to shout. :laugh: :laugh: :laugh: Ed

That's not shouting...

THIS IS SHOUTING!

SWest wrote: Use the clear tube test to identify which carb is leaking.
Steve

Will do. I think it's number 4 since I found a droplet forming at the base of the float bowl but will confirm. Thanks guys.

T

Tvag06 wrote: That's not shouting...

THIS IS SHOUTING!

Maybe you haven't noticed, but all others on this site use a normal size, black font. (hint, hint). Ed

It's an attention getter for sure. :woohoo:
Steve

Maybe use green next time . Made it easy to read . Didnt even need my glasses .

An interesting result from the clear tube test. #3 & #4 leveled in the same location just below the lip of the bowl. #1 leveled at the seam (a few millimeters higher). #2 did not release any fuel when opened ?. So something is going on. I pulled the carbs and bought a sonic cleaner to run them through. Then I'll take a close look at all the internals more closely. Thanks guys.

Carb 1


Carb 2 - no fuel

Carb 3


Carb 4

After an ultra Sonic cleaning and inspection, put the carbs back on tonight. Started up fine, but...

#3 carb is gushing fuel out both boots. I've got a spare needle valve from the 440 project I'm going to try and swap out of there. Of course the problem carb couldn't be 1 or 4 (conveniently on the outside of the stack) :dry:

I'm sure the oil is contaminated as well. Smells gassy. :sick: