NCY 171cc Big Bore Kit - 61mm | No Case-Cut for GY6 QMB139 or QMK engine codes

or QMK engine codes

139QMB-based 50cc / 80cc engines with the following engine codes:

we really recommend 1100-1250

Rattler 50 (Standard & Buck 50) Genuine Scooter Co

and other QMJ/QMK/QMI variants SYM / Lance Fiddle II 125/150

NCY 171cc Big Bore Kit - 61mm | No Case-Cut for GY6 QMB139 or QMK engine codesNCY 171cc Big Bore Kit (61mm) No Case Cut for GY6 150 The NCY 61mm Cylinder Kit is the only 171cc upgrade available in the U. S., designed to fit without machining your engine cases. Featuring a specialized 62. 9mm outer skirt, this aluminum cylinder drops directly into standard GY6 150cc blocks. It is the ultimate "weekend project" for riders demanding a massive jump in torque and acceleration without the need for professional machine shop services.