My carb saga continues.

So, I've been having a leak out of carburetor 3 (second from the right... assuming they're numbered 4, 3, 2, 1 from left to right). I thought it was flooding because it's been coming out of the overflow nozzle on the bottom of the bowl. However today I went and cleaned the needles and inside of the carb thoroughly. and I'm still having a leak issue.

I felt the outside of the bowl and there's gas on the outside of it. Where ever it's coming from, it's not coming exclusively out of the overflow nozzle on the bottom. I can't see where because it's one of the two carbs on the inside of the bike, not the outside, so the outside carbs are blocking my view.

I don't know how to figure out where it's coming out of and I'm out of ideas about how to fix this...

They're Keihin CV34 carburetors. They were re-done by Wired George earlier this year. I'm well past the warranty period however, because I didn't have everything I needed to get the bike to even start up again until just last month.

Do the clear tube test.
Steve

Only the 1980 KZ750 carbs have the floatbowls with a functional overflow feature. Your signature suggests you have a 1982 KZ750H model so what's up with that? Look at the photo below and tell us what type of floatbowl you have. The type with the tube sticking up have a functional overflow feature.

Typically when the float needles stick on the later carbs, the ones without the over flow tubes in the float bowls, the fuel fills up the carbs on the inside and the fuel pours out the float bowl vent passages on the inlet bellmouth opening of the carbs and then the fuel flows into the airbox.

Yes, fuel flows to the airbox and drains through the bottom of it.

Not too scientific, but maybe open the drain and flush it on 'prime' maybe wash 1/4 a pint of fuel through it. Whack the offending float bowl with a rubber mallet, and repeat. Sometimes they just stick open.

If not then clear tube test - just a U tube manometer to check the fuel level. There is a kawi part number but it is just a graduated clear tube.

Worth checking fuel levels anyway - anything more than a couple of mm out of spec can cause issues.

edit: you want to change your oil too -that fuel will dilute it, entering the crankcase through the breather vent in the airbox..

Remove carb from bike ....set on table fill carbs with gas and see where gas is coming from. May have to leave over night if so stabilize then so don't to fall over.

Nessism wrote: Look at the photo below and tell us what type of floatbowl you have. The type with the tube sticking up have a functional overflow feature.

The type on the left. I've got the bronze tubes sticking up. The originals I sent to WGCarbs didn't have it though.

Nessism wrote: Typically when the float needles stick on the later carbs, the ones without the over flow tubes in the float bowls, the fuel fills up the carbs on the inside and the fuel pours out the float bowl vent passages on the inlet bellmouth opening of the carbs and then the fuel flows into the airbox.

This happened on the original carbs when I first got the bike.

So I suppose the ones WG sent me were of an older model than the ones I sent him...

The leak seems to be coming from the bowl itself, because if I wipe my finger under the bowl (but not the overflow valve on the bottom) I get fuel on my finger. However above the bowl, it's dry... So it's basically coming out there in addition to the overflow nozzle...

I'm trying to scrounge up a way to mount the carbs off the bike so I can test the levels... I don't exactly have a good place to do it, and my landlord refuses to clean previous tenants stuff out of the garage so I can have room to do any real work.

Here's a photo of the inside of bowl from the offending carb. I don't know what the dark red stuff was. Might be ethanol, might be rust... I installed a filter and the stuff has stopped appearing in the bowl.

I found this photo on my phone from the first time I took it apart to try to fix this problem. Figured it can show that I do in fact have carbs of a different model than what my bike came with, given the above pictures...

Looks like rust residue. Maybe rust in the tank is keeping the float needles from sealing?

I thought it was rust too, which is why I put the fuel filter on, and since doing that it's stopped... The tank has been cleaned and gelled professionally just before putting everything back together, so I don't know how it could have gotten any rust in the lines, been but... I've blasted it all with carb cleaner and it couldn't be cleaner. Also, the red residue has stopped appearing in the bowls... and it's only this one carb, not the other 3, which is having this problem.

The leak seems to be coming from the bowl itself, because if I wipe my finger under the bowl (but not the overflow valve on the bottom) I get fuel on my finger. However above the bowl, it's dry... So it's basically coming out there in addition to the overflow nozzle...

It can be difficult to find the source of gss on the outside the bowl but if its carb #2 or #3 (left to right 1,2,3,4) there's a good chance it might be coming from the fuel inlet T fitting. The o rings on the T can dry up and leak.

JR wrote: It can be difficult to find the source of gss on the outside the bowl but if its carb #2 or #3 (left to right 1,2,3,4) there's a good chance it might be coming from the fuel inlet T fitting. The o rings on the T can dry up and leak.

If it's 1234, left to right, then it's carb 2 that's offending. All of the hoses and fittings are brand new, and they're dry when the engine is running. It's only the outside of the bowl that gets wet with fuel, not the carb body or the hoses.

The hose clamps however are the wire type, and they might be loose... So I'll check to see if any fuel is coming out of them, but I doubt it.