Leaky Float Valves or something else?

Hey everyone
I got a second 550 (exactly the same as my first one :lol: ) I set my fuel height to 3.3 mm on all 4 carbs which is roughly what the tk-22 website suggests. I'm still getting fuel in my crankcase. My fuel valve and needle appear to be fine but I don't know if they are the problem. Before spending 120 bucks on new valves I don't need, Does anyone know a way to determine where the fuel is coming from?

It sound like you have 2 problems.

One would be the petcock. If it is stopping the flow of fuel as it should when the engine is not running fuel will not flow into the crankcase. To test the petcock you can remove the fuel line from the carb rack and direct it into a can or jar. Also, if it is a vacuum operated petcock remove the vacuum line that runs from petcock to the carbs and route it into the can or jar because sometimes the diaphragm inside the vacuum operated petcock fails and lets fuel run from the petcock through the vacuum line down into the engine. With the engine off and the petcock not in Prime or Reserve if it is a vacuum operated petcock, or with the petcock turned to the OFF position if it is a manual type, no fuel should flow into the can or jar. If it does, the petcock should be rebuilt or replaced.

Second problem would be at least one of the float valves. They can stick open if any grit or crud gets stuck in them. Since you adjusted the fuel levels, i suspect the float problem is intermittent or gradual. I would clean them carefully and see if that stops the leak. If it doesn't you could remove the carbs and attach them to a board that has 4 holes bored to align with the output throats of the carbs. Then if you attached a fuel line to the carbs you could see which ones are letting fuel pass through and work on those float valves to stop the leak. Once you correct the leak you should install an inline fuel filter to prevent any other crud from getting into the carbs. Ed

Thanks for the reply Ed. I rebuilt the petcock the other day but noticed there is a small leak still when i move the tank around. I'll take it to the dealer and see what they say about it. I noticed the #2 airbox boot had gas in it so I'm assuming the overflow problem is coming from that float valve. Does anyone have any experiece with the rusty riders rebuild kits? I ordered gaskets from them before and they work fine but I've never used any real carb parts from them before. I want to make sure i get this right the first time because that air box is a pain in the ass to take off even with the new boots.

I had trouble with my float valves leaking. I went with viton rubber tipped float needles and the leaks stopped. I personally believe you should be able to leave your petcock in the prime position indefinitely while parked without leaks. With the viton tipped float needles I now can.

nickleo373 wrote: Hey everyone
I got a second 550 (exactly the same as my first one :lol: ) I set my fuel height to 3.3 mm on all 4 carbs which is roughly what the tk-22 website suggests. I'm still getting fuel in my crankcase. My fuel valve and needle appear to be fine but I don't know if they are the problem. Before spending 120 bucks on new valves I don't need, Does anyone know a way to determine where the fuel is coming from?

The fuel is coming from the gas tank and it is getting past two different mechanical valves:

petcock
carb fuel valves

Whats the best way to remove the valves without damaging them?

After you get the float bowls off it should be obvious. Do them one at a time so you don't get the parts mixed up. I would not worry about adjusting the float height at the start by bending the metal tab that pushes on the float needle. Just tap out the pin that holds the float and remove the float. Remove the float needle. The only thing holding that in was the float so just tip the carb over and let it fall into your hand. Now there is one screw holding in the brass float needle seat. After you remove that screw pull the seat out with needle nose pliers with care not to damage the inner surface that the float needle sits in.

I would just buy new float needles with viton tips. They seat better than the all metal ones. If you are in that far why not just replace them. You could do the same with the float needle seats but I have had good luck reusing those. Also if it were me I would pull the jets out and clean those as well. In for a penny in for a pound. If you pull the pilot screw, engine side of the carb, first screw it all the way in to just touching the bottom while counting the turns. Set them back to that when you are done. I would get new viton o-rings as well. If you clean with spray carb cleaner just spray the removed parts. Don't spray any rubber parts because the carb cleaner will damage them. The reassemble.

After you put the carbs back on the bike set the petcock to prime. Leave it there for at least an hour to see if the float valves are leaking. If they are there will be gas coming out of the carb. If gas is coming out, something is wrong and you need to figure it out. Finally get a clear rubber tube and stick it to the drain at the bottom of the float bowl. Aquarium stores sell clear tubing at the correct diameter. Hold the tube up and open the float drain screw. Gas will fill the tube up to the same level inside the float bowl. It should be just below the edge of the float bowl. If it is too high or too low, you need to pull the carbs back apart and bend that tab on the float that pushes on the float needle.

There you are done. See wasn't it easy?

Thanks. Do you have a link to where I can find the Viton tip needles?

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