Big Bore Kit – Convert 50cc to 72cc


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Big bore kit with big valve head for converting your 50cc engine to 72cc.

The kit is a creation of our very own, displacement has been increased from 49cc to 72cc. Various parts were tested to find the very best combination.
The resulting power was increased by around 33%, slight downhill increased top speed to 53mph (+8mph), steady uphill increased top speed to 39mph (+7mph), acceleration was increased drastically.

Kit includes -
Big valve head 23mm/20mm
Cast cylinder
Nibbi PE17FL carburetor
Red air filter
Intake manifold
Head and cylinder gaskets
Piston kit with rings
Spark plug

Barrel dimensions -
Bore diameter - 47mm
Cylinder sleeve length - 88.7mm
Outer cast length - 63mm (face to face)

Made to fit - YX, Lifan, may fit other engines (check dimensions)

Additional parts that may be required -
Throttle cable
Carburettor spacer set ( Available in our store - ENP016-2 )
24mm exhaust gasket ( Available in our store - MXA0194 x5 )
Valve cap covers ( Available in our store - MXF0178 )
Take off plate and gasket ( Available in our store - MXF0134 )
Cylinder head rocker inspection cover and gasket
Timing chain cover and gasket

Please note - The head is provided as seen within image one, no covers are included. Typically the engines original ones would be utilised.

We advise that a mechanically able person should install this big bore kit, valve clearances will need setting upon installation.

This product is designed for race purposes only, as such no warranty will be provided.


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