T5 Jetting Advice

Anything related to Vespas... ask tech questions, post helpful info, or just read and learn.
registered user
Posts: 3
Joined: Tue Mar 24, 2020 11:51 am
Main scooter: Vespa T5 classic

Wed Mar 25, 2020 12:14 am

dek Avatar dek
2nd Class Ticket
Mar 16, 2020 at 3:55pm
likePost Options
I am looking for some advice on where to start with the jetting for a T5 malossi 172 with a si 26/26g carburettor also with bgm big box exhaust.
Or is there any online pages with set ups.


paul d
registered user
Posts: 292
Joined: Thu Jun 30, 2011 10:00 am
Main scooter: T5 172 Tv 240
Location: Galway Ireland

Tue Mar 31, 2020 11:07 pm

I'm not sure if this will help but my T5 172 is running on a standard 24/24 with a scorpion exhaust. I've upjetted the main to a 125. I'd say a 125 or 128 main jet would be a good start for your set up, everything else as standard. I couldn't see a big box exhaust needing a bigger main than a scorpion expansion. I've dialled out the mix screw a bit as well and I'm running a 21 tooth clutch. With a sito plus (122 main) mine would pull a 22 tooth clutch. Might be worth a try on yours. They are a great kit but they rattle in a big way! I'm mentioning this to ease your mind for when you hear your engine running for the first time. Smooth they aint!

Post Reply Previous topicNext topic
  • Information
  • Who is online

    Users browsing this forum: No registered users and 1 guest