This Universal Parts 50mm Big Bore Cylinder Kit fits 50cc 4-stroke 139QMB engines, upgrading bikes to 81.3cc based on a stock stroke of 41.4mm!
Specifications:
139QMB-based 50cc / 80cc engines with the following engine codes:
Don't see your engine listed? If the engine code includes "QM" or "FM", this product is compatible with your vehicle.
NOTE: You may need to modify your engine case to accommodate the larger cylinder.
About MotoTec USA: Since our beginning in 1989, MotoTec USA has become a major supplier of parts and accessories for vintage and modern scooters. We have everything you need, from wear-and-tear items like tires and oil filters to after-market parts from brands like Malossi, NCY, Prima, YSS, Dr. Pulley, and more.
