When the throttle closed the revs come down but also with slow "popping/very slow idle" sound then back to normal idle after few seconds (the idle when the scooter stands still). This also happens when I go downhill.
I saw most vespa scooters here (most are P series) have nice smooth decreasing revs sound when the throttle was closed even after fast acceleration.
Is it normal for older vespas to have that kind of down revs sound?
My scooter:
Vespa VBC1T Super
- Modified stock IGM exhaust so it "breathes" freely
- Stock 20:15D dellorto carb
- Idle jet 42-140 with 2,5 screw out, before was 42 no air corrector with 1,8 screw out
- Main jet 160-BE3-102, Up jetted from 98 main because the WOT was lean (the electrode was cream white)
Someone said it was from the idle circuit, which is too lean. But It still happens, even tough I use richer (42) idle jet with mixture screw set richer, also swap to leaner idle jet to get more screw out from the mixture screw.
This is how it sounds, sorry if the video is only when the scooter on stand. But this is what it sounds like when the throttle closed
https://www.youtube.com/shorts/3T4T9XhyZ4I
Thank you