Cost-effective replacement belt for everyday use. Good flex and outstanding grip and can easily be used in lightly tuned engines. Suitable for 139QMB/QMA engines with 12” or 13” wheels or original dimensions of 788-18-30. As a guide, the distance between the crankshaft and the transmission input shaft (this is where the clutch bell sits). This belt is suitable were this measurement is approx. 28 cm Dimensions: 788-18-30