Monster Big Bore Kit Replacement Cylinder Head

If you purchased our 90cc monster big bore kit and need a replacement cylinder head with valves installed, here ya go! This will only work on a QMB139 engine.

- Intake Valve: 21.5mm
- Exhaust Valve: 18.9mm
- Intake Port: 24mm
- Exhaust Port: 22mm
- Valve length: 62.3mm (works with 64mm valve cam tower)