Vespa PK50 POLINI 90 kit

[lukas]

Hello. I need some technical help. I own vespa pk 50 xl.


What is the difference from normal px50?


I have POLINI d.50 (85cc) kit mounted, Proma exhaust and stock carb. I bought it like this. I can reach aprox 70kmh but its quite slow for 85ccm.

What carb shoud i use that it would breathe like it should? Ignition setup?

Its funny, because i have other twostrokes and carbs are way bigger. Another moped 90ccm with original porting, works perfectly with 24 carb. I dont understand how can a vespa engine with polini 130 for example use oem carb with bigger jetting?


First and second gear are really short. Third is ok, fourth longer. I was thinking about primary transmission. What is stock ratio and what would you suggest?

Thanks

[hrvespa]

If you still got the stock carb then its a 16mm dellorto (16.12 or 16.14??)

You could try the 19mm carb from the pk125 or the 20mm carb from the pk125ets but you would need to get the complete manifold to go with it.

Your primary gearing is probably
14/69 (4.93) or 15/69 (4.60)

Could look for something around
24/72 (3.00) or 22/63 (2.86)

To keep costs down you could look for a used pk80 primaries or V90 (think it should fit).

Try placing a thread in the wanted section. You'll probably get something a bit cheaper there as there's plenty of people that will help out supplying parts.