Modern Vespa

Hello everyone, I have some questions about jetting the 177cc upgrade for my PX. I bought this kit from SIP > https://www.sip-scootershop.com/en/product/tuning-kit-polini-sport-177-cc-for-vespa-px125-150-e-lusso-95-98-my-11_10104000?usrc=177cc%20kit

So upgrades are:
-177cc Polini cas iron PnP
-24/24 Carb
-SIP Exhaust
-Polini intake

I can't seem to get the jetting right, I plugged in main jet 130 that came with the kit and it seems too rich, now after riding some time (To be honest now the weather is much warmer, cca. 30C as opposed to when I installed everything 18C-22C.) I live at little above sea level if that is valuable info.

My question for you guys is: Has anyone this exact same setup and what was your solution to fine tuning it? Is there even a generalised solution or do I have to take it to some guy with the super sense which can do it "by feel"?
Any input is appreciated

BR

The 130 with the Polini setup sounds correct.
If the package came with larger jets, install those and see if you feel a performance difference at higher rpms when the main jet is doing its job.

Are you familiar with drilling the main jet feeder hole in the 24/24 carburetor?

To be honest with you, not really. Up jetting seems counter intuitive. What is the logic behind it? I tought i should down jet since my spark plug looks like this (see att.)

Logic behind it is if it gets worse, you will know AND you will not seize your motor. If I told you to go leaner jetting, you could seize the motor and then we would both be in trouble.

Now that I can see the spark plug is black, if you have smaller main jets, slowly start to downjet until you find a good balance of performance without seizing the motor. So maybe 125 MJ?

Ran well before?
Clean out the filter.

I'm surprised the kit includes that guy

SIP ships these with an ungodly huge 130 main to be safe. It's way too big unless you've heavily modified the ports and intake or have a massive expansion pipe.

Listen to MJ.

Read this wiki.

Wiki [D] Guide: SI Jetting Chart + How to Tune an SI Carb


Buy a set of jets and work your way down.

https://scooter-speed.com/dellorto-vespa-si-main-jet-set-bgm-pro-115-138-jb-2599119/?searchid=0&search_query=bgm+jet

Higher air-flow filter vs stock filter connected to bellows/frame, up until it clogs from road dust.

Air flow from above a hot engine also magnifies oxygen density loss (goes rich) riding in hot weather.

*The above involves some speculation
My one experience with it is in a landfill somewhere.

On engine I'd done for my mate the jetting is:
AC 160
BE 3
125
52/120

Spec is:
Polini cast 177
Jasil sport crankshaft(similar to Mazzucchelli I think)
SIP Road 3.0 exhaust
SI 24/24, fuel passage drilled to 2.5 mm
Original air filter, drilled above jets
Original carb case lid

IMHO:
Polini intake isn't good solution as it sucks hot and dirty air right around the engine.