Hoca 50mm QMB139 Performance Cylinder Kit
Please see our Warranty & Returns Policy.
We recommend that you use our QMB139 performance cylinder head (see Related Items) with this set as some stock cylinder heads will not fit. Use with an un-modified stock head can cause serious engine damage.
*You may need to modify your engine case to accommodate the larger cylinder.
- Upgrades to 80cc
- Cylinder Bore: 50mm
- Cylinder Sleeve Outer Diameter: 54.9mm
- Wrist Pin Diameter: 13mm
- Total Piston Height: 34.8mm
- Compression Height (from center of wrist pin hole to top edge of piston): 18.3mm