
TOP PERFORMANCE Big Bore Cylinder Kit (ref. 9921160) — designed for urban scooters of 50 cc, this kit increases displacement to 68 cc to provide more power in the city. The new removable cylinder head increases the contact area with the coolant, lowering temperatures within the cylinder-piston assembly and allowing for the utilization of new compression settings suited to these thermal values.
Main features: diameter Ø 47 mm, stroke 39.2 mm, displacement 68 cc, high-silicon Racing piston. Timing diagram: exhaust 199°, transfers 127°. Geometric compression ratio 14:1 (actual 7.3:1). Squish 0.9 ±0.1 mm.
Delivery contents:
Compatible notably with YAMAHA AEROX R (SA421) 2016, MBK NITRO 2016, and APRILIA SONIC 50 GP 2015. An ideal kit for those looking for an increase in displacement and a design focused on thermal reliability for urban use.