Considering completely new engine

Getting a little tired of tuning old 50cc engines... I am considering to buy a completely new 125cc enging for my Vespa 50 Special (1982), any standard engine that will fit my smallframe Vespa? (that can be purchased here at SIP)

Hi LaRocca


Yes, please tell me more. The Vespa in mention is a V50S from 1982, however the engine is a PK50XL (with 75cc cylinder and a perfromance exhaust). It would be great to re-build this to a 125cc, having it to run like a 125 without totally killing the engine.

Please advise, could you give me a nice setup for rebuilding this engine?


Greetings for the cold North

Hi dude


Why do you not use your 50cc engine to transform in ai 125cc or higher ??


Basically the only thing you have to change is the crankshaft and the cylinder.


If you know what type of engine do you want to build i can recommend you some stuff...



Primaries will need changing too for a 125 upgrade and also the cylinder studs.