Modern Vespa

Hi guys sorry if this has been done before, looking at getting a little bit more speed out of my 2005 px125 all pretty much standard apart from a sports exhaust, question is what size jet am I looking at getting for the different exhaust and maybe doing the filter mod? I have a standard 96jet on at the mo, cheers 👍

Moved to NSM.

depends on the exhaust, really. more than likely you'll wind up with something in the 100~110 range. so, buy a bunch of jets and start a jetting loop to get you where you need to be.

My original setup with a 2003 PX 125 MY had a sip road 2.0 and unrestricted piaggio air filter. I went from a 96 jet to a 101. Its about 1-2 pt up for the air filter and 4 for the road 2.0. On a 102 jet it was a little bit rich but all scoots differ. Buy a 104, 102, 101 and work down until you are happy with your plug colour. Does make a good difference to performance and the cheapest mod for a good power gain.

I wonder which part of the spark plug that tells exactly main jet result? Is it the bottom part of the inner insulator or the top of the plug thread?

This is good. Better still post a photo of your plug on here for expert views. If you doing sip 2 and deristricted filter 102 will be fine, mine was a 101 om standard 125 as 102 a bit rich but better be rich than lean and you can adjust . You will love the setup, big difference in performance allround. Use a 7 heat grade plug too.

All you need to know here:

Is derestricted filter means we drill a hole inside the hearth-shaped of air filter?

It's actually light brown, but looks lighter on camera.

I use B7HS. These are results from WOT, it's richer when low to mid-open throttle. Not a brand-new plug, i guess i'll test it on a new plug later.

Perfect 4 stroke plug but this kind of plug colour is nothing to be proud of on a 2 stroke. Too lean. Although it may or may not heat seize, running that lean will wear the top end out quicker than desired.
Slightly hot atm but the B7HS will be ok when running a bit richer

Should be darker hot cocoa.