Vespa 50n

hello , is it possible to run Vespa 50n with Pinasco 85cc with original exhaust & 16.10 carburetor ? 

What is the correct size for main jet ? Now I use 50 starter jet & 45 main jet but there's no power ...

Hi there,

 

yes, it's possible. The engine would start, but... imagine a marathon runner with a clamp on this nose  - he doesn't get any far...

for a 75/85 cc cylinder you need defintely an SHB 16/16, better a SHB 19/19 plus a banana type exhaust...
In case you need  top speed, you need to change the primary gear in the gear box, othewhise (without chaged gear), you only get around 6-8 km/h more compared to the speed in the original papers