50cc 2 Stroke Cylinder Kit with 40mm bore, 10mm wrist pin & 50mm stud spacing Compatible with Yamaha Minarelli and Chinese (1E40QMB, 1PE40QMB) engines Compatible with Yamaha Minarelli Chinese & European Scooters & ATVs.
Some engines use a 12mm wrist pin, be sure you order the correct one.
Partial list of models that may use this kit: As always, compare closely to your old parts to be sure this is the one you need.