RAGGED MOTO TECHNICAL TOOLS

Motorcycle Carburetor & Jetting Settings

A technical reference and calibration tool for motorcycle carburetors, providing factory specifications and modified jetting calculations.

For fuel-injected bikes → See alternate calculator

UK & Europe

USA & Canada

Calculate jetting without selecting a motorcycle

FINE-TUNING

WHEN CORRECTLY SET
Instant throttle response right off idle, a smooth and steady tick-over, and quick starting.

TROUBLESHOOTING

Idle is uneven or keeps changing
→ The mixture is too lean (too much air). Add fuel using the air/fuel screw in ¼ turn increments, or install a larger pilot jet if it won’t settle.

Hesitation when opening the throttle from idle
→ Turn the air/fuel screw in ¼ turn increments to add more fuel; fit a larger pilot jet if the screw is already at its adjustment limit.

Engine sounds muffled, splutters, or smells like unburnt fuel at idle
→ The mixture is too rich (too much fuel). Reduce fuel using the air/fuel screw in ¼ turn increments, or step down one pilot jet size.

WHEN CORRECTLY SET
Smooth, strong power delivery from ¼ to ¾ throttle with clean acceleration, no flat spots and a crisp engine note.

TROUBLESHOOTING

Flat spot or hesitation when rolling on the throttle.
→ The mixture is too lean. Raise the needle one clip position (move clip down) to add fuel.

Engine feels sluggish, splutters, or takes a moment to clear.
→ The mixture is too rich. Lower the needle one clip position (move clip up) to reduce fuel.

WHEN CORRECTLY SET
Clean, full-power acceleration at wide-open throttle with the engine pulling freely through the entire rev range.

TROUBLESHOOTING

Engine feels flat or loses power at ¾ to full throttle
→ The mixture is too lean (too much air). Increase the main jet one size to add fuel.

Engine splutters, struggles or fails to rev out at full throttle
→ The mixture is too rich (too much fuel). Decrease the main jet one size to reduce fuel.

Fine-tuning: Change one adjustment at a time and retest before making another change.

Baseline setup information intended as a
starting point only. Specifications may vary
depending on modifications, fuel type,
altitude, climate and regional differences.