Spaco (Dellorto) SI Carburetor 20/17 D - Vespa P/PX, Stella

Restore the crisp throttle response and reliable idling of your classic Largeframe with the Spaco Si 20/17 D Carburetor. Manufactured in India under strict license from Dellorto, Spaco is the only company authorized to produce these legendary SI-series carburetors to original Italian specifications. This 20/17 non-injected model serves as the perfect OEM replacement for 2-port vintage engines and provides a significant performance upgrade for older models currently running restrictive 20/15 units.

Key Performance Features

• Dellorto Licensed: Built using original Dellorto tooling and specs, ensuring factory-correct fuel atomization and air-mixture control.
• Performance Upgrade: The 17mm venturi provides increased airflow over stock 20/15 carburetors, resulting in better mid-range pull without requiring airbox modifications.
• Non-Injected Design: Specifically engineered for traditional "pre-mix" fuel systems found on vintage P/PX and Largeframe series scooters.
• Complete Setup: Arrives pre-configured with a versatile jetting stack suitable for most 125cc to 150cc stock applications.

Comprehensive Fitment Guide

These carburetors are an aftermarket part and not part of the original manufacturing process. The difference between your original and this replacement is that on your original carburetor, the air corrector and idle jets are shorter, so they sit almost level with the top of the carburetor, whereas on this replacement, they are taller and make the air filter difficult or impossible to install.

There are two ways to correct this:

• You can remove the air corrector and the idle jet from your original jet stack and place them in your new carburetor.
• You can purchase a P200 air filter (SKU 131083), which has a heart-shaped cutout on the bottom to accommodate the larger jets. This means that there are some slight differences between them and the original equipment on your scooter. It doesn't mean that the carburetor won't work; it just means there will be a little more installation effort beyond "plug and play."
  

*Early VNB/VBA models may require a later-style carburetor box for proper clearance.

Technical Specifications (Stock Jetting)

• Idle Jet: 42
• Air Jet (Air Corrector): 160
• Atomizer (Mixer): E1
• Main Jet: 98

Installation Note: This aftermarket replacement features "tall" air corrector and idle jets.  If these jets interfere with your stock air filter, you can either swap the shorter jets from your original carburetor or install a P200 Heart-Shaped Air Filter (SKU 131083) for a perfect fit.

Tuning Tip: Jetting is something that requires trial and error. See more on

• Spaco SI 20/17 D — Dellorto-licensed, built to original Italian specifications in India
• 20mm inlet / 17mm venturi — non-injected, for 2-port vintage largeframe engines
• Performance upgrade over stock 20/15 carburetors — better mid-range airflow
• Pre-configured with stock jetting: idle #42, air corrector 160, atomizer E1, main #98
• Includes carburetor-to-airbox paper gasket and idle mixture screw with spring and needle

Type: SI 20/17 D, non-injected | Inlet: 20mm | Venturi: 17mm | Idle jet: 42 | Air corrector: 160 | Atomizer: E1 | Main jet: 98 | Origin: India | SKU: 150490

Vespa VNB 125 (1959–66) | Vespa VNC 125 Super | Vespa VNL GT/GTR | Vespa VNX P125X | Vespa VBA 150 | Vespa VBB 150 | Vespa VBC 150 Super | Vespa VLA GL150 | Vespa VLB Sprint 150 | Vespa VLX PX150E | Vespa VSD Rally 180 | Genuine Stella 150 2T. Early VNB/VBA may require later-style carb box. Verify model and engine type before ordering.