A carburettor is what mixes the air, oil, and fuel in the right proportions, then sends it to the cylinder(s). A better carb will give you greater power, but will use a hell of a lot more fuel. E.g. 21-carb is far more powerfull, but uses up GALLONS more fuel and oil than a 16-carb.

Barrel sizes 14-15-16 mm

Choke sizes 9-10-12-14-15-16

Idle circuit drawing mixture from main jet

Flat throttle slide

Semi-automatic strangler starting system

16-17-18-19mm clamp-on connection to engine

Choke sizes 15-16-17-17.5-18-19-20-21 mm

Independent starting circuit

Left or right-hand mixture adjustment

24 or 23mm clamp-on fitting, or 25mm elastic connection to engine

32mm plain or M32 x 1.25mm threaded connection for trumpet/air filter attachments

Choke sizes 15-16-17-17.5-18-19-20-21 mm

Independent starting circuit

Left or right-hand mixture adjustment

24 or 23mm clamp-on fitting, or 25mm elastic connection to engine

32mm plain or M32 x 1.25mm threaded connection for trumpet/air filter attachments