Big Bore GY6 Cylinder Rebuild Kit With Large Valve Head For 139QMB 139QMA And 147QMD Scooters Mopeds ATVs And Go Karts 69mm Long Valve Heads For More Power And Performance

GY6 69mm Big Bore Kit with Large Valve Head (1 kit)
✔️ 69mm long valve head kit for 139QMB/139QMA/147QMD engines boosts power

This Big Bore Cylinder Rebuild Kit upgrades the GY6 engine with a 69mm long valve head to increase horsepower and torque for scooters, ATVs, go-karts, and mopeds. It's designed for 139QMB, 139QMA, and 147QMD platforms commonly found in lightweight riders and off-road machines. Includes large valve head and compatible components; note that the engine side cover gasket is for the short-case 8-bolt version.

✅ 69mm long valve head compatible with 139QMB/139QMA/147QMD engines
✅ 18.5/20.5mm large valve head vs stock 16/18.5mm
✅ Glixal piston rings with DLC wear-resistant coating to cut friction and protect the cylinder sleeve
✅ Rocker arms compatibility: if original head uses 64mm valves, swap to kit's rocker arms
✅ Engine side cover gasket included for short-case 8-bolt version

💡 What is a big-bore cylinder rebuild kit used for in GY6 engines? This handy upgrade improves power and throttle response for everyday riding.
- Increases displacement and improves airflow with a larger valve head
- Enhances torque for hill climbs and quick acceleration
- Reduces friction with DLC-coated piston rings to protect cylinder wear
- Fits 139QMB/139QMA/147QMD scooter, ATV, and go-kart engines