Upgrade your 50cc scooter to achieve more acceleration and top speed with a 47mm/80cc Big Bore Kit. This kit includes everything you need, including the A9 Cam and Rocker Arms assembly. No more guessing games with valve measurements, as we have thoughtfully included the rocker arms assembly to ensure compatibility.

With fast shipping and hassle-free returns, Pitmoto is the brand you can trust for high-quality scooter upgrades.

Please note that this kit is not recommended for inexperienced installers and should be installed by an experienced scooter or motorcycle mechanic. The valves will require adjusting, and the timing must be set correctly. Failure to correctly set the timing can result in catastrophic engine damage.

Fits the 50cc 139QMB engine.

Kit includes:
Cylinder  47mm
Piston, rings, pin and clips
Head with valves
HP Cam A9
Gaskets and Hardware

Specifications:
Cylinder Bore:   47mm / 80cc
Valve Length: 69mm
Piston: 47mm / 80cc
Piston Pin: 13mm
Bolt Hole Spacing: 50mm (center to center)

Cam Bearings:  16002/P6 (32mm diameter)
Cam Sprocket: 34 tooth

Note: This kit is NOT recommended for inexperienced installers. It is highly recommended that an experienced scooter or motorcycle mechanic installs it. The valves will require adjusting and the timing must be properly set.

  

Important Parts Notice:  Not all replacement or upgrade parts come with instructions. It is the customer's responsibility to have common knowledge of the installation or hire an experienced installer. We are not responsible for any damage that may be caused by any of the items we sell, whether installed by you or a professional. We are not required to provide step-by-step instructions or technical support. In any case, we will always do our best to help you with any technical question you may have. 

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Important Notes

Address Change Request
An address change request will never be accepted. Please make sure you choose the correct shipping address before completing your order. If you need to change your address you will have to cancel the original order and place a new order with the correct shipping address. 

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