These pilot jets will fit all Arreche/Amal Carburetors up to 21mm.

The pilot jet supplies most of the fuel at low throttle openings. It has a small hole in it which restricts fuel flow. Using both the air screw and the pilot jet you can adjust the air/fuel mixture and the performance of your carburetor from idle to about 1/4 throttle.

If your scoot only rides at walking speed for the first 30 feet or so then your pilot jet is too small. If your engine sputters up to 1/4 throttle then your jet is too big.