Size of jet for Racing cylinder 75cc DR Vespa

Hello everybody,

My small frame is a V5B (50 Spécial) and i bought a racing cylinder 75 DR Vespa. I have a problem with my carburator jet (duse). I bought a 60 jet size but when i start the engine, the jet is blocked. When i put the 51 jet size which is the orinal jet (for 50 spécial), there is no problem. The scooter is really OK.

So i would like to know if it’s dangerous for my engine to drive with this size of jet. IF yes, could you telle me what size i have to put ?

I’am sorry, my english is not very good !!!

Thanks a lot.


That's way too small and it's likely to sieze on you.Have a look at this so you can gauge what sort of size you should be running for your set up.