Sizing at sea level:
With UNI filter 120-125
With UNI filter and low restriction exhaust 130-135
With UNI filter, low restriction exhaust, A12 cam, performance coil & CDI and NGK Iridium spark plug 135-140
Test procedure:
1. Run engine at less than half throttle a minimum of 15 minutes to close electric choke
2. On a 300' or 100 meter stretch or greater, run the engine at wide open throttle
3. While still holding the gas pedal to the floor, cut the ignition
4. Remove the spark plug and inspect end for color
a. White - Increase jet size
b. Tan/Brown - Correct jet size
c. Black - Decrease jet size
5. Clean spark plug with brass wire brush and check the gap prior to next test run
Hints:
1. Change jet size by 2 or 2.5 for fine adjustment by 5 for coarse adjustment
2. Reduce jet size by 2 or 2.5 for every 1500 ft or 500 meters of elevation
3. Stock fuel delivery may not be sufficient above a 130 main jet and may require larger diameter fuel lines and less restrictive fuel filter
4. Once main jet is selected, the air/fuel mixture screw can be adjusted for optimum idle
credit to buggydepot.com
Many people own a scooter nowadays for the great fuel economy that they all possess, but many have found that if you have a foreign make or model that finding someone in your town to repair a broken scooter may be a failed effort. I dedicate this blog to helping those with a scooter in need of repair advice. Most makes are similar to the above photo.
That is basic knowledge to someone who has worked on small engines... but keep on truckin there are many people who need a site as informative as this one has been thus far thnx
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