Brand new GY6 100CC BBK BIG BORE KIT for Chinese 4 stroke Scooters & Mopeds Upgrade 49cc 50cc to 100cc

The best way to get more RPM, the maximum direct upgrade kit for GY6 50cc 139qmb engine without modification.

Why is this advertised as the best? Simple put, we don't throw in useless parts to make the BBK look enormous. Every component is carefully selected to boost performance, not just for the show. Without A9 cam and 69mm valves and rockers, your engine will not reveal the full potential of the BBK. You might find those so called 100cc BBK for a little cheaper, but they are all lack of the very key components to maximize your engine performance. We are the only supplier with the key combo included. Most of our customers are returning customers and experienced builders who know the true value of this kit.

Big Bore kit includes

Bore kit works with: