Big Bore Kit – Convert 50cc to 72cc

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%. The top speed was slightly increased downhill to 53mph (+8mph), remained steady uphill at 39mph (+7mph), and acceleration was drastically improved.
AMAZING FROM A 50cc 4-STROKE!

Kit includes:
Big valve head 23mm/20mm
Cast cylinder
Nibbi PE17FL carburettor NOTE - Carburettor colour is silver, not black/red as per picture.
Red 45mm air filter
Adjustable intake manifold
26mm carb spacer and gasket set
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 compatible parts that may be required:
Nibbi Vortex Throttle (Available in our store - Part No. DNY-YY)
Nbbi throttle cable (Available in our store - Part No. YMX-CB-black  or  YMX-CB-red)
24mm exhaust gasket (Available in our store - Part No. MXA0194 x5)

We advise that a mechanically able person should install this big bore kit; valve clearances will need to be set upon installation.

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