You may now clean the choke plunger and spring assembly, taking care not to lose any pieces! A bike that runs good at sea level will run rich at 10,000 ft due to the thinner air. Clean the sealing area on the carburetor body that the float bowl seals up to. At the end of the sleeve on the bottom is the main jet, so it is effectively shut off. The clip position can be changed to make an engine run richer or leaner, fig 4. If you cant bend it with our fingers, use a pair of needle-nose pliers.
This low pressure also causes a low pressure inside the carburetor. If the screw is turned in, it reduces the amount of air and richens the mixture. Step 2 - Airbox removed 2. Also clean the float bowl seal. Since 1968, Mikuni has been making parts designed to give you precise fuel mixture metering while still delivering smooth throttle response. But I just can't get enough! Unscrew and remove the cap. When these two lines are lined up, the engine will be idling.
Screw it all the way in until it becomes snug, then unscrew it the amount recorded in disassembly step 4. A main jet size of 350 would be multiplied by 0. Mikuni carburetor operation and tuning Mikuni Motorcycle Carburetor Theory 101 Motorcycle carburetors look very complex, but with a little theory, you can tune your bike for maximum performance. Most of the tuning for this range is done to the jet needle, and not the needle jet. Now find the half-way point between both of the lines on the throttle housing. There should be 2 vent lines per carburetor and a fuel line. Now write this number down, and you can remove the pilot air jet by fully unscrewing it.
Step 4 - Slide and jet needle 4. Using the same technique as for the pilot jet, clean the main jet. The carb was also used on some Toro lawnmowers and E-Z Go golf carts and even the older Kawaski Mule 550. Determine the correct air temperature and follow the chart over to the right until the correct elevation is found. It must be remembered that carburetor jetting is determined by the throttle position, not engine speed. Place another piece of tape on the throttle grip and draw a line while the throttle is at idle straight across from one piece of tape to the other.
The thicker the taper, the leaner the mixture since the thicker taper will not allow as much fuel into the venturi as a leaner one. It will only go in one direction. It will be located between the fuel tank and the fuel pump, often on the right side of the engine compartment when sitting on the seat. Juice up your bike with this race-winning gear today at Summit Racing! Altitude, Humidy, and Air Temperature Once the jetting is set and the bike is running good, there are many factors that will change the performane of the engine. If the adjustment screw is in the front of the carburetor, it will be the opposite. Now open the throttle to full throttle and draw another line directly across from it on the throttle housing. The higher the number on the main jet, the more fuel that can flow through it and the richer the mixture.
Remove the spark plug and look at its color. Was this review helpful to you? I need a better pipe than a Tecno Circuit to unleash it's true power, but ill get one soon enough. Adjust the pilot circuit until the motorcycle runs cleanly off of idle with no hesitations or bogs. Mikuni American is not responsible for mechanical damage or personal injury caused by an improperly installed carburetor, operating conditions, or its installation and tuning by the vehicle manufacturer, dealer, mechanic or private individual. To use this chart, jet the carburetor and write down the pilot and main jet sizes. Atmospheric pressure is a powerful force which exerts pressure on everything.
The jet needle is a tapered, needle-like device that rises and lowers in the needle sleeve with the slide valve. Altitude, air temperature, and humidity are big factors that will affect how an engine will run. I'd rather not as my pocket book is flaccid and bill-less. I see them all over the net for pre 87's. Altitude affects jetting since there are less air molecules as altitude increases.
This image is the property and Copyright of Polaris Motor Co. It should be a light tan color for more info on reading spark plugs click here. Now twist around to clean. Can't wait to see what it does after that! I suspect that all of them are off of 2 cycle carts. The first step is to find where the engine is running poorly, fig 7. The moving air going through the carburetor will pick up fuel and mix with the air. Take carburetor to a comfortable working area.
The choke system will add fuel to the engine to compensate for the fuel that is stuck to the cylinder walls. Remove the wire and set aside. Re-assembly For this section refer to the diagrams in previous sections if you are still not familiar with the parts. The venturi is a restriction inside the carburetor that forces air to speed up to get through. Use the chart from fig 9 and determine the correction factor.