Cylinder -DR177 cc 3 Ports (lathed off for PX80 engine casing)- Vespa PX80 (crankshaft PX125 necessary)

CYLINDER
The cylinder kit offered here is originally intended for use on the PX125 engines. To be able to use it on the engine housings of the PX80, the cylinder base diameter was turned by a professional company.
It fits without further modifications in the engines of the Vespa PX80 models.

ATTENTION: The cylinder base of the 172/177cc cylinders is very thin. By turning it by about 1mm it will be further weakened. To prevent damage due to fatigue fractures, we strongly recommend to modify the engine housing (spin out) instead of using a turned cylinder. A good alternative are the 125/150cc and 166cc cylinders. These offer sufficient wall thickness due to their smaller bore to allow them to be used safely in continuous operation with a machined foot.

Crankshaft
The original crankshaft of the PX80 models has only 48mm stroke.
Therefore it must be replaced with a crankshaft of the PX125/150 models with 57mm stroke.
Professionals can also use a PX125/150 racing crankshaft with 60mm stroke.
The then necessary stroke compensation is done by a head or foot seal with 1.5mm (or depending on the desired control angles in e.g. 0.5mm head and 1.0mm foot seal).