Modern Vespa

So I promised myself the new kit at christmas, but whilst the UK is in lockdown not much to do so fitted it already!

Thought I would post my setup as a guidline as the kits instructions and jetting kit is pretty off the wall and I dont think any real help.

2011 px125 zapm engine prefix

22 tooth cosa clutch
std primary and gearing
Mazzi race cut crank.
Sip Flywheel with starter ring.
Sip flywheel side bearing.
Sip Road Xl exhaust
Ducatti cdi

Si24 carb, T5 carb slide, airfilter no gauze and drilled, carb oval hole covered.
MAIN JET 127, MIXER BE3, AIR 160
IDLE JET 52/140
Idle mixer screw adjusted to 2 turns from open.
SIP Fast flow fuel tap

Malossi 178cc cast iron kit.
long reach plug

Sip Speedo MK2

The engine has no metal ground away as in transfer port matching or at the carb inlet, everything is bolt on upgrades.


The kit itself caught the starter ring on the flywheel, so I very very carfully ground away some metal right on the transfer port, not good for such a long established manufacturer, I painted the barrel and let the flywheel scrape away at the paint, its only a small area that need attention.
So far I have ridden the scooter around town and a few 50mph runs, but nothing major yet, I dont have the faster roads near by, but all is well, it pulls nicely in a higher gear when riding in traffic.

I did have an issue with boging from a standing start, I know my carb is clean inside the fuel gallerys so I decided that the progressive circuit wasnt being influenced enough or at all causing the engine to almost die when i started rolling, the fix was to wind in the idle mixer screw, the one poking out the back, this in turn lowered the tickover which I adjusted by screwing in the tickover screw, one out the top, this then moved the slide further along its track opening up the progressive circuit outlet to the income gulp, solving the bogging issue completely. My tickover when clutch is out is around 1400 rpm, clutch pulled in and gear engaged around 1200 rpm, all ish.

Before writing this I pulled the sparkplug and its the most perfect chocolate brown you could hope for, but as I say no high speed runs yet, that will probaly come much later, but so far very pleased with the performance and running temps.

I wouldn't be doing any high speed runs with an AC160. Might be ok with an AC140.
Ducati electrics a solid choice. Otherwise, nice safe road tune.

Hi Jack, another silly question from me 😜.
Im not doubting what your saying, Im just trying to understand better.
I understand that standard 200 px Si24 carbs are set up with a BE3 and a 160 Air jet.
My 177 Pinasco runs the same set-up.
Living in Switzerland I speak German and when I check the German Scooter Forums they recommend in the Si Carb Bible:
Für fast alle Kits über 150ccm habe kann gesagt werden, daß das Mischrohr BE3 (Bild 6.3) mit der HLKD 160 (Bild 6.2) optimal ist!

Translated:
For almost all kits over 150ccm it can be said that the mixing tube BE3 (Fig. 6.3) with the Air Nozzle 160 (Fig. 6.2) is optimal!

Thanks for your valued feedback..

Robbie

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It's about time we had one up on the GSF. If you can run an AC160, at wide throttle, for long periods over thousands of miles, then you have a lower power scooter that will last forever. Probably some German humor.
Btw: can't imagine how many vowels in HLKD in German.

Thanks Jack...

HLKD
Haupt Luft Korrektur Duse.... 😜
Main Air Correction Jet