Would a 50cc cylinder fit a 125 vespa primavera engine?
Thursday, August 26th, 2010 at
9:49 pm
I have a 125 primavera and would like to convert it to a 50cc, is it possible to put a smaller cylinder on it?
No, it’s not. The piston opening in the top of the crankcase is too large, and the studs won’t line up. By the way, you would also need a new cylinder head.
possible to put a smaller cylinder ? Probably- but unlikely to find a 50cc cylinder kit readily available that size. Minerelli base engines for scooters and small cycles used to have the same case and crankshaft for 45cc to 90cc with the 70cc a square bore/stroke. smaller cylinders were for different markets where under 50cc got a break in licensing or such, larger cylinders for the cycle markets where up to 125cc were in same license class but insurance break under 100cc gave slight market advantage or a under 5hp engine was the legal class break. 125cc is common European class break, the under 100cc sometimes has slight market advantage, the US federal light cycle class break is 150cc so some engines are designed to use same crankshaft in 125 and 150cc sizes- mostly as a wide bore cylinder in 150cc and more square ration 125cc. the 99cc engines tend to be the smaller bore than stroke variations for special market. A few engine cases noted to be available in 50cc and 125cc- but crankshafts are different strokes also. 50cc newer Vespa supposed to have its own little engine case with a big bore 70cc available in limited markets- the one noted was the 5hp class in a couple Canadian provinces. Primavera 125 may have a 99cc and 150cc cylinder available , maybe under different name. Aftermarket- not OEM- cylinder kit may be available but I doubt small as 50cc. You trying to get into a no drivers license required for 50cc class?.