TOPIC:

Here's a mystery.
I've replaced all the jets and seals on my TK26 carbs. Adjusted float heights to be just right according to the factory manual.
To test for leakage I've made DIY IV and connected it as alternative fuel source for bench testing.

For the first few hours all good. No leakage. If I leave it overnight it stars to pour fuel trough the air intake of one carb.
And, here is the funny part, each time it leaks from only one carb and every time it's a different one (1,3,4,1).
So, it takes more than a few hours to start leaking. When it starts to leak it doesn't stop until all the fuel from IV is gone.

At first i thought that I've set my IV too high and created too much hydrostatic pressure so the fuel forced its way past the float needle.

But, no. Last time top of the fuel in IV bottle was 2 feet above the center of the air intake. That shouldn't cause any problems. Or?

Maybe pilot jets plugs? Any thoughts?

Float valves letting by.

From the net : "Those carbs need pilot jet plugs. If they are missing the fuel will flow".

kevski wrote: Float valves letting by.

Maybe... I have 4 new sets of float valves, seats and seals installed. I have tested them with my lungs. Air does not get trough if the carbs are upside down.
But, maybe...

Pilot jet plugs have nothing to do with fuel level or eliminating leakage.

Did you measure fuel level of the carbs? Did you fully break down the carbs and replace the O-rings on the inlet Tee and fuel transfer tubes? Those O-rings get exposed to ozone and typically dry up hard as a rock.

Nessism wrote: Pilot jet plugs have nothing to do with fuel level or eliminating leakage.

Did you measure fuel level of the carbs? Did you fully break down the carbs and replace the O-rings on the inlet Tee and fuel transfer tubes? Those O-rings get exposed to ozone and typically dry up hard as a rock.

Yes. Float height is set according to manual. I did the clear tube test. Inlet Tee and fuel transfer tubes are all ok. No leaks there. They just overflow and start to leak from the air intake. I have changed everything (seals, jets, float needles and seats...). All new. One thing I did not replace are the floats. Am I having a buoyancy issue here ?

Just some thoughts from SW developer. Not a mechanic.
1. float needles, seats and floats are designed to withstand a certain amount of hydrostatic pressure.
2. petcock is usualy at the certain height, so it creates a certain hydrostatic pressure on the float assemly.
3. if you raise the hydrostatic pressure by raising the fuel column (lifting the fuel source higher), you will have a breach.
4. if your petcock and float needles, seats and floats are working as they should, you will not have a leak.
5. you need float assembly in whole to do the job, petcock, float needels, seats, seals and float hight to be just right.

1. Yes, but as the fuel level increases in the bowl you will get increasing pressure on the float valve to remain closed. If fuel continues to flow after the valve is closed then you most likely have a bad match between valve and seat. You should check to see if there is any dirt or varnish on the valve seat that might prevent the valve from closing properly.

2. Depends on whether the petcock is open or closed. If open then the pressure is a result of fuel height in the tank. If closed, and it should be closed when the bike is not running then you must have leakage past your petcock. Either replace it or rebuild it.

3. Maybe...refer to item 1 above.

4. Correct.

5. The fuel system is tolerant of some errors so things don't need to be exactly according to spec.

When you set your fuel level did you check to the top of the meniscus or to the bottom? How did you measure the distance?

I recently had one letting by, I removed the carbs and the offending valve and used a wooden cocktail stick with a little metal polish to clean where the valve needle seats, also wiped a little polish round the needle, I rinsed them clean, reinstalled no leaks, the metal to metal ones are renowned for this and this is how I have always cured it, also turn your peacock off when not running the bike.

Are your new float valves and seats OEM?
Meaning, are they Kawasaki parts?
Did your carbs leak before you changed out the parts?

I would stick to OEM for carb parts. Too many horror stories.


www.ngwclub.com/forum/viewtopic.php?f=1&t=37139

www.motorcycleproject.com/text/carb_rebuild_parts.html

F64 wrote: Are your new float valves and seats OEM?
Meaning, are they Kawasaki parts?
Did your carbs leak before you changed out the parts?

I would stick to OEM for carb parts. Too many horror stories.


www.ngwclub.com/forum/viewtopic.php?f=1&t=37139

www.motorcycleproject.com/text/carb_rebuild_parts.html

I know. That's life.

kevski wrote: I recently had one letting by, I removed the carbs and the offending valve and used a wooden cocktail stick with a little metal polish to clean where the valve needle seats, also wiped a little polish round the needle, I rinsed them clean, reinstalled no leaks, the metal to metal ones are renowned for this and this is how I have always cured it, also turn your peacock off when not running the bike.

All 4 brand new. From DE.