Modern Vespa

So I am still having trouble with the PK, rememberd something from when I had a moped which was that my gas cap wasn't venting and I had to clean it.

Thought this might be why it's shutting off after some distance as it isn't showing any clear signs of overheating.

Removed the cap and yeah, I can't blow through it and can't see through it.

I belive it has a valve in it, but even now after some cleaning with IPA, an ultrasonic bath in hot cleaner and some prodding with some wire I can only barely sometimes get it to blow through with a can of air duster(no compressed air available where I am atm). Moving in the spring loaded arms up and down makes no difference in how hard it is to blow through either.

This seems like way waaay too much resistance to me? Anyone have a Zadi gas cap they could check? Would be wonderful if this is what my issue is

I just tried my brand new one. Blows through with only slight resistance. Looks like you need a new cap.

Was just about to write that I fixed the cap!

Blew it out with 6 bar of compressed air and now I can blow through it with just some slight resistance

Hopefully this was THE issue I have been having, messing up my jetting and the cutting our on the highway.

Limped the Vespa to my garage where I have a compressor with the cap only screwed on 1/8th turn or so and it didn't cut out on me.

My attempts to clean with other stuff seem to have made it worse as I got about 20m all down hill before it died on me. That's when I tried to unscrew the cap to the minimum it would hold and I made it all the way to the garage like that!

Hopefully this helps someone in the future!