Modern Vespa

hello guys. i need help on my carb jettings. i am currently using a cast iron polini 177, 24.24g carb, polini venturi air intake/filter, and a sip road 2.0 exhaust.

my current jetting:
idle jet: 50/100
air corrector: 120
mixer: be4
main jet: 101

at around 1/8 to 1/4 throttle i notice a little power loss during acceleration. idle also goes way up when engine is warm. any advice would be a big help.

First you need to be certain your engine is air tight with no air leaks, fast idle could be an indicator.

The main jet seems too small, I'm running a 112 main on a Pinasco 177 with 24g. Have you done any plug chops? Need to establish what is too big and work down. Easiest to see what 2nd gear can run clean from a rolling stop to WOT.

I'm not a fan of the polini air filter for 2 reasons, they reduce the inlet size of the air box because of the rubber connector which can't be beneficial. Also they ingest warm less clean air from the engine compartment. A standard bellows seems to be preferred.

I've been running the standard bellow on my HRS Vortex for 15 years. those air filters are a solution looking for a problem. . .unless you are in some kind of dusty wasteland.

Hello. My compression tester is still the way. Will test it as soon as it arrives. I will be ordering a main jet kit, a taller airbox, a 52/140 idle jet, a be6 and be5, and a 140 air corrector.