Modern Vespa

Looking at building an engine using new SIP cases for a SF 125 (VMA). Going to use a VMC 135 cylinder.

going to to run a 24mm PHBL, Rotary valve

would like to use the EVO cases that have 3-hole manifold input. It appears Polini does not off a 3-hole manifold to fit both a 24mm carb and the older chassis', ET3 etc. I really do not want to cut the frame. https://www.sip-scootershop.com/en/product/crankcase-sip-evo_24301000?usrc=sip%20crankcase%202-hole

Polini does offer a 2-hole manifold for the 2-hole SIP cases for 24mm carb. There would be machine work i would have to do to get the VMC cylinder to fit; namely, removing the dust cover for flywheel. https://www.sip-scootershop.com/en/product/crankcase-sip_24303000?usrc=sip%20crankcase%202-hole


anyone played or heard anything good with this conversion piece? your thoughts? https://www.scooter-center.com/en/intake-manifold-inkl.-carb-rubber-strohspeed-for-carburettor-dellorto-phbl22/24/26-conversion-of-clamp-to-rubber-compound-cs-30mm-28-5mm-30mm-3332351kt?number=3332351KT

perhaps something else in the market i am not seeing?

i kinda hate the idea of adding one more area for an air leak.

Jon

I had that same issue with the motor you built for the green SF.
Ultimately had to trim the opening after it was painted.
Hated doing it but couldn't find another solution.
The only other potential way is to fabricate a flange, have some 24mm ID tubing bent and use the rubber mounted.
There might be a market for these conversion intakes to fit PHBL 24-30 to early V smallies using 3 stud rotary intake cases.

I know you said rotary build, but could you remove the reed from this one? Or just leave it in?

https://www.sip-scootershop.com/en/product/intake-manifold-polini-by-sip_21501151?usrc=Polini%20reed%20manifold

I did this. Used the 30mm manifold and machined / welded a new end piece…

https://www.sip-scootershop.com/en/product/intake-manifold-polini-phbh-28-30-tmx-27-30-pwk-28-30_21504350

that's good. a little lathe work and TIG weld it. was hoping i have overlooked an off-the-shelf item, but this may have to work.

Nothing ready-made for 3 hole cases on SF, that's why I went that route. Only difference I used a CP24…

it's so crazy, you can buy 3-hole 16, 19, and 28-32. for whatever reason, nothing in the 24 range.

The only ones I see are for PK, not sure if there's a figment issue with the frame.

Yes. Fitment issue.