Strange "downgrade" : 50 cc cylinder for vespa PK 125

Hello Friends. I have strange question: is it possible to install 50 cc cylinder on the motor of PK 125s?The registration of the scooters comes in my country and looks I'll need "downgrade" my vespa from 125 cc to 50 cc for a while! Thanks in advance for all the replies.

Hi dude


To create a 50cc you have to change the crankshaft the exhaust and the cylinder.

Also the ignition timing has to be changed to 19 degrees.


I guess it would also interesting to change the hole engine.

So you can take the 125cc and save it or sell it.


A used 50cc engine is basically not to expensive and than you can fix it by your own by changing for example all gaskets bearings a new sparkplug and oilseals.