Modern Vespa

This is a sort of spinoff of this past post:Leak....cylinder to cases

I just received my new stock cylinder including a wrist pin, piston and a set of rings. I was looking at the new piston and it has one less port than the old piston. Now I am not sure what is the correct one to use. Is the old piston wrong and the new piston is right or visa versa?

your old piston was for a "three port" cylinder that has a third transfer port opposite the exhaust port.

your new piston and cylinder are as they should be.

Wow, and I thought that scoot ran fabulous with the incorrect piston. Curious to see how it runs with the correct piston. BTW which way should the arrow point?
And, thanks for the info.

the three port piston will run just fine in a two port cylinder. it's not "correct" but will work.

the arrow points toward the exhaust port.