Guide for Carburetor Tuning

I read some guidelines and tips on how to tune your carburetor to its best settings. I hope that I can also help you by sharing this knowledge. There are to screws to be adjusted, the Idle speed screw and the Idle mixture screw. For Idle mixture screw settings, 11/4 turns from slightly seated to make it in stock settings and for Idle speed screw just turn 1/2 clockwise from its engagement point. The start your motorcycle and let it heat up its operating temperature. Idle speed screw is made for adjusting the RPM and to increase the rpm just turn it clockwise and counter-clockwise to decrease the RPM. The range should be from 950 RPM to 1050 RPM. In terms of the Idle mixture screw it is for the adjustment of your engine running performance. By turning the screw clockwise it will make the engine to run poor and counter-clockwise to make the engine stumble. Set first the screw to make the engine runs poorly and set it again to make the engine stumble. Take note of the position of both screw for poor run and stumble. The set the screw halfway just between the two position you just have noted. If you encounter inconsistent in your idle, the manifold may be leaking or damage. After achieving a strong idle test your motorcycle by riding it and maintain the speed of 40 - 50 mph. In this way you can check if the condition of fuel and air mixture. The sneezing sound in the air cleaner indicates lean condition of mixture and rich condition of mixture if the engine stumble or vibrates. In terms of RPM operation, the intermediate jets is the one responsible for it. Changing the intermediate jets from different sizes may gives you the best performance and right fuel supply for your engine. Always remember to adjust the Idle speed and Idle mixture screw after changing intermediate jets. In case of testing the main jet performance you run your motorcycle from 50 - 70 mph. If your engine backfires adjust the size of the main jet to bigger one and if the engine does not accelerate decrease the main jet size. Changing this jet to a larger size will delay the signal to the main jet, therefore aiding with high speed tuning. This also aids with tuning an engine that is fitted with an exhaust system that is not intended for high performance. Remember that using open pipes or performance pipes may affect the performance to be obtain from carburetor. The stock size for the main jet is 40 and if you want to change it normally the range will be from 50 - 60.