Float Level Adjustment
By: Canadian Dave
Before you consider rejetting your carburetor you need to insure you don't have any mechanical problems that are mimicking poor jetting. Float level problems are common so checking the float bowl fuel level is a great place to start. You might suspect that the fuel level is out a whack but wouldn't it be great to be able to confirm it before making any adjustment. A fuel level gauge can be installed on the carburetor and the fuel level visually checked. You can order a fuel level gauge from Kawasaki. The part number for 1989 to 2000 KDX200/220s is M18 x 1.0: 5701-122. The factory service manual does a good job of explaining how to use it. If you need some help just post your question on the JustKDX Forum .
Before we go any further remember that gasoline is extremely flammable and explosive. Make sure the area youre working in is well ventilated and that there are no sources of ignition like open flames etc.
There are two common methods used to set the float height. Ill go through both. They both work well so the choice of which one to use is yours.
Step One -Turn the fuel tap to the off position and remove the carburetor. Thats an overly long word so from now on lets just call it the carb. Drain the fuel from the carb hold it upside down and remove the float bowl. Just remove the four Phillips head screws and that step is done. A word of caution, youll be playing with some fairly small parts so I would strongly suggest doing this job over a clean work surface so if some thing does fall youll have a hope of finding it and so it doesnt get all dirty. A smart trick is to use a couple layers of paper toweling or a clean rag on the surface. That way if some thing does fall it wont jump away and hide.
Step Two - The second step is common to both methods. Before setting the fuel level you first need to confirm that the plastic tip of the float valve needle is in good condition. Both procedures assume it is. Over time the tip of the needle wears, doesnt seat properly and alters the fuel level. Thats normally why your fuel level is out of whack. To get at the needle you first need to remove the floats pivot pin. Before you do take a look at the carb open in front of you. There arent a lot of parts there but they need to be reassembled the same way they came out. You see the metal tang just in front on the pivot? Thats where youre going to make your adjustment. Also note that there is a small metal clip that attaches the needle to the metal tang. Be gentle removing the floats so you dont damage it. OK, remove the pivot pin and then the floats. Pull the needle from it seat and have a look at the tip. It should be smooth with out any deformation, grooves, scratches etc. If there are replace it with a new one. Now that you have inspected the needle you can reassemble it all again but dont reinstall the float bowl.
Float Valve Assembly Needle Inspection
As a side note, if youre disassembling the carb now would be a great time to clean the internals, especially if your KDX is more than a couple years old. It is an easy job all youll need is a can of carb cleaner and a couple more tools. Youll want to remove the pilot jet using a bladed screwdriver and the main jet using a 6mm socket. Spray carb cleaner through both jets and through the rest of the carb. Follow the instructions and warning on the can. Allow the carb to dry, visually check that there is nothing obstructing the jets and reinstall them.
Method One - Measuring the Height of the Float
This method requires a set of calipers. With the carb upside down, tilt the carb until the tang on the float just makes contact with the needle rod protruding from the float valve. At this point the distance between the bottom of the float and the float bowl mating surface should be 16mm ± 1mm or 0.63" ± 0.08". Remember the carb is upside down so the bottom of the float is facing you. If the distance is out side of this range gently bend the tang and recheck. Ideally you would reassemble the carb and recheck it with the fuel level gauge. If you dont have a gauge youll have to trust you set the height properly.
Measure the distance between the bottom of the float and the float bowl mating surface (#1). The distance should equal 16 mm +/- 1 mm or .63" +/- 0.08"
Method Two - Setting them Parallel
This method is similar to the first method. It isnt quite as accurate but works fine if you dont have access to a set of calipers. In method one when you measure the distance between the bottom of the float and the float bowl mating surface the two are parallel to each other. If you use a straight edge for a reference, a feeler gauge works well, and place it on the float bowls mating surface you can visually check to see that the two are parallel to each other. It helps if you angle the feeler gauge towards the float to reduce the distance between the two a little. Tilt the carb the same way you did in the previous method and watch for the tang on the float to just make contact with the needle rod protruding from the float valve. If the two are not parallel at this point the bend the tang and recheck. Ideally you would reassemble the carb and recheck it with the fuel level gauge. If you dont have a gauge youll have to trust you set the height properly.