16mm Carb Tuning Instructions

To set the high and low speed, turn them all the way in just until they barely stop, DO NOT OVER TIGHTEN! then back them out the suggested amount.

Set the low speed first:
The low speed should be adjusted for good throttle response when initially accelerating. Make SMALL adjustments, keeping the screw between 1/2 turn out and 2 turns out

Set this for best initial acceleration, not for top speed. Make an adjustment then test that setting, then adjust some more. Best way is to do starts with a screw driver in your back pocket, stopping to make small adjustments until the scooter is very quick when you hit the gas.

As you adjust your low speed setting, it may affect idle speed. Idle is adjusted by turning the screw that acts as a stop for the throttle fulcrum.

Set the hi speed next: The high speed is the slotted screw (black usually) that sticks out the side of the carb. The high speed needs to be turned in while the engine is at peak rpm, Turn this screw in until the rpm just slightly increases (due to lean condition which will damage the engine if left in this setting), then turn it out 1/8 of a turn. Do this on a bench for a close setting, but do it while riding for the most accurate setting.

You can adjust the high speed by free revving with the back wheel off of the ground and holding the throttle wide open while adjusting the screw but this is not accurate.