Need help leaning out fuel/air mixture

If fuel is coming out of the overflow you may have one (or more) of the three problems described below. Remember - NO SMOKING or other activities that could ignite the fuel while working on carbs!

The float valve is not sealing. This may be (and probably is) just a matter of some minor dirt in the float valve and is very simple to remedy and can be done with the carbs still on the bike. Turn off fuel; drain carb by loosening big brass screw near bottom; and remove the 4 little screws on the bottom of the carb bowl. This will enable you to remove the carb bowl. You will then see the float. If you carefully remove the float you will see a stubby little needle that mates with a brass orifice; together, these two pieces are the float valve. Assuming there is no obvious damage to the needle or seat, use a Q-tip and some carb cleaner to clean the seat of the orifice and the needle. Be careful not to bend the tang that is attached to the float. This tang is the piece that the bottom of the float valve needle rests upon, and it determines the fuel level in the bowl, so bending it will change the fuel level. With the float valve cleaned it should no longer leak. To prevent a re-occurrence a quality inline fuel filter should be installed between the fuel tank and carbs. If there was damage the needle and seat should be replaced as a set; they are available.

The brass overflow tube inside the carb bowl is damaged. When you remove the carb bowl you will see a brass tube attached inside and rising toward the top of the bowl. This is the overflow tube and it leads directly to the overflow nipple on the bottom of the carb. Normally, the fuel level within the bowl rises somewhat close to the top of this tube. If the tube becomes cracked or separates from the bottom of the carb bowl fuel will flow through it and out through the overflow hose. Checking the condition of the tube is very easy after you have removed the carb bowl from the carb. Simply hold the bowl level and fill it up near the top of the tube with water or alcohol and see if it leaks. A slight crack in the brass overflow tube can be difficult to find. You can connect a rubber tube to the overflow nipple, fill the bowl with water, put finger over the open end of the brass overflow tube and blow in the rubber end and look for bubbles. If it does the best remedy is to replace it although some folks have found creative ways to repair them.

The fuel level is set too high. This condition occurs when someone has bent the float tang as mentioned above. This condition can be checked using what is referred to as the "clear tube test." The test involves attaching one end of a clear piece of flexible tubing to the carb drain hole and holding the other end of the tube above the bowl/carb joint. When the fuel is turned on it should rise in the tube to a level 2.5 - 4.5 mm below the bowl/carb joint. If the fuel rises higher than that level it may run into the cylinders or over the upper end of the brass overflow inside the carb bowl (mentioned above) in which case it will run out the overflow hose. This condition is corrected by removing the float and gently bending the tang to raise the float valve needle position. Doing this may take several tries before achieving the desired fuel level.

Correcting each of these three conditions involves removing the carb bowl. This task can be made easier if a short screwdriver bit is used, and depending on which carb you are fixing a mirror may help you locate the screws on the bottom of the carb bowl. Also, it is not a bad idea to have a new carb bowl gasket available in case the old gasket is damaged while removing the carb bowl. Ed

fatcat70 wrote: So I'm currently in the process of the clear tube test. Numbering from left to right... Carbs 1 and 2 are leaking gas out of the little holes in the bottom of throat (see picture) but the fuel in those clear tubes isn't quite to the level of the gasket. Does this mean there's still too much fuel in the bowl?

The fuel is too high. It wouldn't come out of the air jet if you were doing it properly. It should be 1/8-1/4" below the gasket.
Steve

650ed wrote:

kaw-a-holic wrote:

fatcat70 wrote: Do I need to buy special tubes for it or should I put more effort into Jerry rigging tubes to fit the nipples tightly ?

.............This is a very important step to carb tuning. I use one of these, worth every penny: www.z1enterprises.com/product/ZSM01-208

That really is a bargain! Before those were offered for sale I made a very similar tool for my carbs, and it cost me more to make one than than Z1E is asking for one already made. Ed

i have two of them so I can see two bowl's level, fed from the same fuelTee.
I do it off the bike, carbs mounted through two old manifold couplers to my work bench or shelf ...using mineral spirits instead of gasoline.

I was finally able to work on the carbs some more. I'm still doing the clear tube testing and it's almost correct now. However one thing I'm noticing is the clear tubes are taking a couple minutes to fill up with fuel. Is this normal?

Are you using the stock fuel tank and existing fuel lines, with at least a half gallon of fuel in it? Or like me with single tube about the same length, holding it vertical to get the same aprox "head pressure" as a gas tank and filling it with a funnel, etc.

Clogged petcock strainers?
Steve

missionkz wrote: Are you using the stock fuel tank and existing fuel lines, with at least a half gallon of fuel in it? Or like me with single tube about the same length, holding it vertical to get the same aprox "head pressure" as a gas tank and filling it with a funnel, etc.

I have always wondered if this is the cause of my float issues. I built a stand for my Keihin 34 carbs, then created a page for it in the Tools area.

kzrider.com/forum/21-tools/604016-carb-h...-float-levels#744214

kaw-a-holic wrote: use one of these, worth every penny: www.z1enterprises.com/product/ZSM01-208

I don't understand how that $12 for one tube linked above from Z1 would work. Where would the threads go, and why $12 each? Wouldn't you want 4 or 2 based on your # cylinders? I made the ones linked to in my tools post for a couple bone$.

Creation of a signature in a poster's profile which signature includes information about bike year and model in each post is helpful to viewers. The signature helps avoid viewers needing to scroll back up through a thread searching for bike year and model that hopefully appears somewhere in an earlier post.

It's easy to put information in a signature where it shows in all posted messages, past and future.
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If wanting a signature showing information about the bike in posted messages, it's easy to do. Here's how:





Good Fortune!

For the 550 ltd, Tk22 carbs, I have a starting point detailed for the fuel level.

gpzweb.s3-website-us-east-1.amazonaws.co...stmentsAndMaint.html

The drain tubes on the bottoms of the bowls are connection for the clear tubes. Use an 1/8" vac hose and press the end into a larger clear hose. You need a larger hose (1/4" or larger) to prevent false readings from happening. The drain screw needs to only be loosened about 1/2 to 1 turn to see the level rise..

There is a whole site dedicated to those carbs.

gpzweb.s3-website-us-east-1.amazonaws.co...ge/TK22mainPage.html

And if you follow the links in my signature, you can download several service manuals. Grab all of them for reference.

Read the valvetrain warning before working on the valves.

loudhvx wrote: For the 550 ltd, Tk22 carbs . . . The drain tubes on the bottoms of the bowls are connection for the clear tubes. . . The drain screw needs to only be loosened about 1/2 to 1 turn to see the level rise. . . .

Loosening of the drain screw converts the overflow nipple to a float bowl drain nipple.
The drain function -- not the overflow function -- is used by the clear tube test.
The clear tube test won't work on these type carbs unless the drain screw is loosened.

It's unfortunate that the FSM's clear tube test instructions don't mention the need to loosen the drain screw.





Many other Kawasaki models have carbs with drain screws that have no connection with the overflow circuit.
Some Kawasaki models have carbs with drain screws and no overflow circuit.
Mikuni smoothbore carbs have drain screws and don't have overflow circuits.

Good Fortune!

The factory service manual, in my signature, for the Kz550 has it. I said .5 to 1 turn, but the manual says 1 to 2 turns. Go with the manual's numbers. If you open too far, it can start sucking air bubbles in through the screw and that throws off the reading.

The tube at Z1E is for carbs that do not have the drain/overflow nipple. On those carbs, the drain screw must be removed and replaced with the threaded adaptor. Most people work on the fuel level one carb at a time, so one tube is enough.