QuestionI have a kawasaki kmx 200 and have been having problems with the carb can you tell me how to set the fule and air screw thanks john.
AnswerWell, John you are taking "MrHonda" far afield with your Kawasaki MX question, especially when you haven't described the "problems" in detail.
The two main screws on most motorcycle carbs are the idle speed and idle mixture screws. The speed screw is the one centered on the carb body in alignment with the middle of the carburetor slide. If you have the air filter off/carb off you can turn the screw in and out to watch it raise and lower the carburetor slide. That's its only function.. setting the idle speed.
The idle mixture screw, is more forward and adjusts the air/fuel mixture while the slide is down blocking off the main metering passages. There are "air screws" and "fuel screws" on various carburetor designs. Usually the mixture screws need to be out about 1.5 to 2.5 turns. Air screws, which allow more air as you back them out have a blunt end, whereas the fuel screws have a needle-tip design which is allowing more raw fuel to enter the idle mixture circuits.
I did a quick search on "KMX 200 carburetor" and found numerous threads on forums including this:
http://www.thumpertalk.com/topic/1024391-kmx-200-wont-idle/
2 stroke engines are highly sensitive to many factors in the way they operate. You must have good compression, tight crankshaft seals, engine/exhaust systems that are matched up design-wise, a clean carburetor and accurately working ignition system components. Any kind of major wear or modifications to an otherwise stock engine will require re-tuning of the carburetor jetting, which means you have to have a handful of main jets and probably different needles and perhaps idle jets to adjust the mixture settings to match the motor's requirements.
Start from the beginning.... Do a compression test to ensure that the engine is sound mechanically. A vacuum test will determine if the crankcase seals are all intact and working properly. If the ignition side seal fails the engine mixture goes lean and usually seizes. Failing transmission seals will suck the oil out of the transmission causing overly rich/oily mixtures.
These bikes are highly tuned for racing purposes, so you can't troll them around doing trail rides for the most part.
Find a factory shop manual for your bike, which will give you much greater insights into the whole design and tuning process for this model. I have no specifications or other information to share on this model.
Bill Silver
