It was so easy, you only had to modify the variator (the automatic transmisión of the scooter) because the limitation was just a low gear that didn’t let you go faster (think of driving always on first gear). You removed a stop on the variator that let you use the full range and the limit was gone.
Anyway, 2 stroke motors were also easily tunable, and people used to change the escape, carburetor, even sometimes the cilinder was changed to have more power on those little machines.
Norwegian here: When I grew up (I was born in 1980) there was a thriving market for performance parts for "moped"s small motorcycles (max 2,5hp, 50ccm).
You could get replacement cylinders and everything. According to what I heard if you upgraded everything you could get about 16hp out what used to be one of these underpowered machines.
Ahahah pota si! Ho guardato il tuo profilo e ho capito (quanto meno di fama) chi sei! Mi ricordo di aver letto di cubetto, bellissimo progetto! Posso contattarti all'indirizzo email presente nel profilo matlo.me per chiederti da bergamasco a bergamasco un po' come sta andando la tua avventura?
