88cc Big Bore Kit (52mm) - 50cc (139QMB) / GY6 50

88cc Big Bore Kit for QMB139 and GY6 50 Engines

This 88cc big bore kit upgrades a 49cc/50cc scooter for stronger performance. It uses a 52mm cast iron cylinder built for the 139QMB engine family. Riders often pick it when they want a noticeable boost in acceleration and hill-climbing ability. It is one of the GY6 50cc scooter parts that can make your ride feel livelier.

Larger Engine Displacement

Raising the displacement to 88cc gives the engine more torque and a higher top speed. The cast iron body is durable enough for everyday riding. The cylinder bore is precision honed to lower friction and help the rings seat properly, which supports steady engine performance.

Fitting Notes

Fitting this kit usually means machining or cutting the engine case so it clears the larger cylinder skirt. An engine bore tool is recommended for making those changes accurately. Doing the installation carefully helps the engine perform well and last longer.

Specifications

• Material: Cast Iron
• Size: 52mm
• Position: Cylinder
• Fits: CSC Go Max (GO MAX cylinder and crankshaft diagram) with 139QMB / GY6 50 engine

Compatibility

Compatible with:

• CSC Go Max
• Other GY6 50cc (139QMB) scooters

How to choose: Confirm the engine case is 139QMB or GY6 50. This 52mm kit needs the case machined or cut to accept the cylinder skirt.

Where it goes: part #13 on the CSC Go Max cylinder and crankshaft diagram.

Other versions: If you need a 50mm kit for 139QMB engines from 50cc to 81cc, this 88cc 52mm kit is not the right one. Look at GY6 50cc (139QMB) Cylinder Kit 4T (81cc, Iron, 50mm). For the Blue Line 72cc big bore kit with head and 64mm valves, see GY6 50cc (139QMB) Big Bore Kit with Head 4T (72cc, 64mm Valves).

Browse more: GY6 50cc Scooter Parts (139QMB) · GY6 Scooter Parts · Scooter Big Bore & Cylinder Kits · Scooter Parts