Complete 72cc iron cylinder & head kit. This works with most Chinese 50cc 4-stroke QMB139 engines. Pump up that weak engine to a respectable 72cc displacement (and stay on  budget). This kit is not indended to make your scoot a screaming...

Large 2 valve head to help your cylinder breathe better. We recommend a larger intake manifold with this head. And if you're wondering how you can make this even better, check out the Aluminum Racing Valves to go with your new top end.

Polini big bore kit for four valve, 4T, 49cc Piaggio engines. Fits Vespa LX 50, Primavera 50, Fly 50, and the P50 Scootcoupe.

Polini Corsa big bore kit (72cc) for Honda Dio (OEM part number 119.007/R) Includes 47mm piston.

NCY 81cc Aluminum Performance Cylinder Head. Give your 139QMB the power to handle today's city traffic. You can use this cylinder on all 139QMB engines from SYM, Kymco, QLink, Filly 50 as well as other Chinese scooters with the 139QMB engine. Be sure to...

These 72cc cast iron cylinder kits are built with two things in mind; power and reliability. Malossi's years of experience, gained in building for the track, translate to thoroughly researched thermodynamics of cast iron resulting in cylinder kits...

This head will allow your cylinder to breathe better! Works great with the 61mm cylinder assembly. And if you're wondering how can this get even better, check out these Stainless Steel racing Valves to go with your new top end. When changing a...

Elevate your scooter's performance with the Air-cooled 2T 72cc Big Bore Kit. Crafted with precision, it boasts an iron cylinder and a robust 2-ring alloy piston design featuring a 10mm wrist-pin for unbeatable durability and power. Ideal for Yamaha Jog,...