Step one disassembly

Detailed disassembly of 139qmb top end to prepare for big bore kit install.

I'm going to show you in detail how to disassemble and prepare a 139qmb for big bore installation.

In part 2 I will be giving fully detailed install instructions with the #SA88 52mm Big Bore Kit with big valve head.

If you want to maximize the power and speed of your gy6 50cc 139qmb scooter this big bore kit has the largest displacement, largest valves and ports and is the highest quality kit available for the money.