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 junk parts to make the BBK look enormous. Every component is carefully selected to boost performance, not just for the show. For example, without A9 cam and 69mm valves and rockers, your engine will not reveal the full potential of the BBK. Without the larger main jets and paired pilot jets, your engine will perform poorly and even run slower than stock engines. 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

    • Fully assembled cylinder head
    • 69mm high lift valves, best performance valves
    • 69mm high lift rockers, best performance rockers
    • 50mm bore size cylinder jug
    • Cylinder head gasket set
    • 3 up-sized main jets and matching pilot jets to upgrade your existing carb, no need to purchase bigger carb
    • A9 high performance camshaft best performance combo with 69mm set up
    • Piston & Rings set
    • 69mm high lift camshaft holder
    • Manifold

    Bore kit works with:

    • Roketa 49cc 50cc 4 stroke scooters such as Bahama, Maui, Sicily, Tank, Baotian 50QT-9
    • Taotao 49cc 50cc 4 stroke scooters such as GT5, Fastwind,  atm50-a1, cy50-a, cy50-b, cy50-t3, funny 50, Roman 50, Retro 50, Speedy 50, Venus 50
    • SUNL 49cc 50cc 4 stroke scooters
    • VIP future champion 4 stroke
    • Jonway 49cc 50cc 4 stroke scooters such as warrior 50
    • Baja 49cc 50cc 4 stroke scooters such as motorsports SC-50 sun city, primo
    • Zhongshen ZS50QT-4
    • Baotian BT49QT-2, BT49QT-7, BT49QT-9, BT50QT-9, BT50QT-11
    • Fly Scooter 49cc 50cc 4 stroke scooters
    • Tank 49cc 50cc 4 stroke scooters
    • Jinlun 49cc 50cc 4 stroke scooters

    Multiple items can be combined shipping, please look at our other items, thank you.


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