Interactive
Tuning Tools & Calculators
Four tools for 2-stroke mopeds. Pick one, adjust the sliders, and use the numbers as a starting point — then verify on the road or dyno.
Calculators
Port timing
Exhaust Port Timing
Duration, blowdown, and live cross-section diagram with engine presets.
Open tool →
Intake
Intake Length Tuning
Jennings ram, reed vs piston-port equations, scaled tract diagram.
Open tool →
Pipes
Expansion Chamber Designer
Graham Bell tuned length, cone angles, true-scale pipe profile.
Open tool →
Premix
2-Stroke Oil Mix
Interactive premix calculator and ratio chart by engine family.
Open tool →Pair with these guides
- Exhaust porting guide — before you raise a port, measure it
- Carb jetting — after any intake or pipe change
- Build paths — mild / mid / wild parts lists