Cylinder Heads & Valve Covers

Affordable replacement cylinder heads, assemblies & valve covers for 50cc-150cc scooters, ATVs, pit bikes, go-karts, and quads — fixes compression loss, overheating, valve issues, or poor performance during rebuilds. Includes complete cylinder heads (39mm bore for 49cc-50cc GY6 139QMA/139QMB; 52.4mm for 110cc-125cc horizontal; 57.4mm for 150cc GY6 152QMI/157QMJ), YX140 full head assembly (140cc-150cc dirt/pit bike 1P56FMJ), valve cover sets (70cc-150cc, single/dual), and intake/exhaust valve kits (with springs, clips, seals) — durable aluminum/composite fixes on a budget.

Best fits: GY6 4-stroke 49cc-150cc (139QMB/50cc short, 110cc-125cc horizontal, 150cc 157QMJ; TaoTao, SunL, Roketa, Baja, SSR, Coolster, Kazuma scooters/ATVs/go-karts), horizontal engines 70cc-125cc (Chinese pit bikes/quads/dune buggies), YX140 140cc-150cc dirt bikes. Most are plug-and-play direct replacements (some with valves included) for quick top-end repairs or compression restoration!

Need the full cylinder and piston? Check our Cylinder Kits & Big Bore Kits collection for complete upgrades.