Carbs issues

[Stuckinmud15]

I finally got my carbs reinstalled and got a battery. Fired up the bike last night and the bike ran not too bad, until we tried to take the choke off. taking the choke off kills the bike no matter how warmed up it is. Sometimes it will stay on longer but usually dies pretty quick. After sitting for a minute, we noticed they were pissing fuel. WTF?? They also make this back firing kind of sound, but its more like a very quick, stout hiss, and it seems like they do that hiss one at a time and mist fuel out the intake side (not running filter now, waiting on pods).
Ideas?

[natemoen]

Well of it is missing gas out of the intake side then you have gas getting past your float valves somehow. Do you have inline filters in your fuel lines? How clean is your gas tank? Did you replace the o-ring around the needle seats during your carb cleaning/rebuilding?

[DGXSER]

I do agree that it sounds alot like you have float valves not sealing. Did you test them before installing?

Dear old Prom has taken a leave for a while so I will post his simple and elegant test. After you finish installing the float seats, needle valves, and floats and have the height adjusted properly, hook some fuel up to the carb fuel Ts. Any leaks?? No, ok then, lift the floats ever so lightly on each carb to get just a small trickle of fuel to come through the float valves. Now dry that up with towels or compressed air or what have you. Any leaks....no...Ok then, go to the kitchen make a sandwhich listen to a bit of the ball game, watch some news or other whatever while you eat same sandwich, go back to the carbs, and check for any leaking. No leaks? great, put the float bowls back on, set the carbs up level and up right and hook the fuel back up to them. Check for any fuel coming out, any leaks. No leaks? Great...NOW mount them to the bike.

These simple test can save alot of headaches of installing and removing carbs 3-4 times or more.

[Stuckinmud15]

Thanks for the tips. To perform that test do I have to hold the carbs as if they were mounted on the bike? With the float bowls removed obv? And when I put the carbs back together I never did anything to adjust the floats height. And as far as the seats go, I am just going to be looking for leaks coming past the o ring right?

[DGXSER]

For the first test wiht the float bowls removed, the carbs are sitting upside down on the diaphram lids. Look for fuel to leak past the o-ring/seat seal, or through the valve itself. But essentially, you do not want to see fuel around the top of the float valve where it goes into the seat, or any part of the float bowl for that matter as it would all have to run past the needle valve to get in there.

I would definitely check the float heights. Measure from the gasket flange, with no gasket installed, to the highest surface on the actual float. If your valve seats are the push in kind wiht the o-rings, your floats should be at 23mm +/- .5 mm IIRC.

[Stuckinmud15]

Ok so with the tank attached to the carbs, carbs upside down I'm checking for leaks around the seats. And when I move the floats, gas should trickle in.Is there any other way gas could leak in besides bad o rings on the seats? Because I replaced those. I recall a float not moving as freely as the other ones when I reassembled, that was due to a slightly bent pin, but I was able to straighten that out pretty good, or at least so I thought lol.

[DGXSER]

Only causes for gas getting in is leaking o-ring, bad needle valve when they are seated. Now that bent pin could well be an issue. The float needs to very freely move on that pin. Any binding and it very well may not float up and close off the valve.

Test no 2 should show that, or could show it anyway. I think I would just replace the pin. If nothing else it seems if it is bent at all it would be a complete PITA to remove later.

[Stuckinmud15]

Only causes for gas getting in is leaking o-ring, bad needle valve when they are seated. Now that bent pin could well be an issue. The float needs to very freely move on that pin. Any binding and it very well may not float up and close off the valve.

Test no 2 should show that, or could show it anyway. I think I would just replace the pin. If nothing else it seems if it is bent at all it would be a complete PITA to remove later.

I just realized that while I was experiencing the carbs leaking gas, gas was dripping from the carb with the bad float pin. Now I haven't done the test you suggested yet, but would replacing that pin cure the problem of multiple carbs doing that gas misting out of the intake issue?

[DGXSER]

Nope, each carb and cylinder is its own little engine so to speak (from a fuel side anyway) other than they get fuel from a combined source, being the tank or the fuel line to each pair. SO the floa tin one will have no effect on the fuel level in the others.

[Stuckinmud15]

Thats what I thought. Maybe the orings I put on the seats from harbor freight are too small. How much pressure should be used to push those seats down into their holes? They felt quite snug when I put them in.

[cywelchjr]

Thats what I thought. Maybe the orings I put on the seats from harbor freight are too small. How much pressure should be used to push those seats down into their holes? They felt quite snug when I put them in.

Too tight is just as bad as too loose. Did you get the rubber ones or the viton ones? The wrong ones also won't work worth much of for very long either DAMHIK.

[DGXSER]

Cy, they have the Viton but also the Nitrile which will also hold up fine to gasoline. But yes, the plain rubber ones will just about melt down in short order.

[Stuckinmud15]

I got the nitrile ones.