Modern Vespa

The heart in the air filter is also an AC.
If that's the only change you're closer to a 52/140 pilot vs drilled with a 55/160, from my anecdotal experiences.
Made a rich-pop sound video a little while back. Is this what you're hearing?

So am I better with the undrilled air filter and 55/160 until I get the 52/140?

More air (drilled) = leaner , right?

Hal

If you're unsure whether you're rich or lean, pull the choke a little and see if it gets worse or better.

well now my plugs are so fouled the bike wont idle, so i need to wait until i can buy more plugs tomorrow.

h

Drilled = leaner.

None of my kitted bikes run would better with an undrilled filter.
Tried everything except a venturi. Drilled filter still makes use of the heart/filter as an air stabilizer on a moderately tuned bike.
You have to be rich as hell now.

Is that pop in the video what you're hearing?

Did you get a CHT with a threaded sensor?

There has to be something else going on to get a BGM to seize with your last jetting.
Go over Jack's list he mentioned earlier.
PIA maybe, but you have to verify fuel supply before doing anything else. With a threaded CHT you'll know. When the fuel supply/bowl gravity to the MJ isn't sufficient on a long ride, temps will rocket.

Tomorrow back to the oh setup, with a fresh plug and a CHT.

It's possible I'm not getting enough oil or not where it counts. Most likely pull the carb and do new gaskets and hondabond. I'm getting so much oil out the hole in the back of the airbox.

Hal

If you *really* want to know, you need to add an Exhaust Gas Temp (EGT) gauge to the mix. That'll tell you that something is up with the fuel supply well before your CHT.

I had a screw-in CHT on the Smallstate and I was only at about 280 when I seized due to fuel starvation. The EGT would have spiked, telling me I was having fuel delivery issues with plenty of time to slow my roll before I had to stop my roll.

(Yes, an EGT is absolutely going to be added when I put that beast back together)

ok I'm rebuilt and back to the original jetting.

55/160 idle jet
AC140-BE3-125MJ

Carb base flattened, hondabond on all gasket surfaces, CHT back on spark plug with crush washer removed. Happy for the peace of mind.

This is the best tuned I've gotten. Still a little rough when I'm riding nice a repsonsible citizen but hard rides today felt and sounded really good. Barely got into the 190s. Everything seems good.

I woudl really like to try a 52/140 or 50/140 idle jet but I can't find one stateside to save my life. Anybody have one they want to sell me?

H