High Performance Race Gears for GY6 50 139QMB Engine

Performance Final Drive Gears for GY6 50 139MB Engines

Great addition and very easy to install once pressed together.

The larger ration will add the most top end speed with the lowest adding the torque needed for two riders plus hills.

Best used with 70cc - 85cc cylinder kits

Use Caution when adding to a non upgraded engine whichis not suggested.