Newbie: Advise appreciated - 125N engine vs 2 or 3 Port upgrade... pros & cons

Hi All! 

Looking for some advice on engines, and also upgrade options. 

I just bought my first Vespa (actually a MotoVespa, built in Madrid in 1960). It's a 125N, piston ported, 3 gears bike, all original - very nice little scooter - I love it. However, the engine isn't running and either requires a full rebuild or replacing with something else...  




Restoration Plan: 

Given the paint is original and has a lovely aged condition; my plan is to preserve the paint and all body as is and only restore the mechanical elements. 

I spoke to few other vespa people who all said not to bother rebuilding the 125n engine, but to replace it with a 2 or 3 port later engine (Sprint or PX). But a loud voice in my head is telling me to keep it 100% original.

I do not plan on racing this scooter, it will only be used for pleasure and small tours.. 


As I know nothing about any of these engines and would love to hear some thoughts from you all.. 

1) is the 125N engine really not worth rebuilding? 

2) if not, what do people suggest 2 or 3 port  and why? pros  / cons? 

3) If I go with a later engine, what other upgrades are worth considering while I'm rebuilding the engine, gears, cables, breaks and dampers. 


All advice and opinion are very welcome! 


hi all ! would really be grateful for some general thoughts as to the 2 vs 3 Port engine, and other upgrades options worth considering in such a build.