Nasty Fast Parts · Two-Stroke Tech Tools
Carburetor Size Selector v84
Three suggested carburetor diameters for Trail, Median and Race with a comparison to your installed carb.
Shared Builds · Jetting / Gearing / Premix / Engine Tools
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Build & Riding Goal
Carb sizing from modeled two-stroke demand and air speed. Three targets emphasize different throttle-response and top-end compromises.
Relative filling assumption (not a measured CFM).
Recommended Carburetor Sizes
Air-speed comparison
Calculated diameters are starting points for choosing a genuine carburetor. Throat shape, venturi taper, reeds, manifold match, real flow coefficients, engine powerband and riding style matter. A disappointing jetting curve alone does not prove a carburetor needs replacing.