Malossi PHBG Dellorto 19mm Carburetor for Aprilia / Piaggio 50cc 2T


The Malossi PHBG 19mm carburetor kit replaces the standard 17.5mm carburetor in your SR50R. As a kit package, it has been specifically designed to fit the Piaggio Hiper2 engine found in almost all Aprilia and Piaggio 50cc 2T scooters (such as Aprilia SR50R, Sportcity 50 2T, SRMT 50 & Piaggio Zip 50 2T, Typhoon 50)

This carb will fit the stock intake manifold and airbox fittings. Please note that this carb can only be used with a manual choke, no automatic choke is available for the PHBG. Kit comes with a manual choke kit, to be located on the side of the transmission cover.

Main Jet: 5mm

Pilot Jet: Bullet Shape

Needle: W series (W7 and W9 needles commonly work well in these carbs – W16 supplied with carb)

Outlet OD: 23mm (to fit stock instake manifold)

CLICK to view PHBG Tuning Items


Malossi PHBG Dellorto 19mm Carburetor for Aprilia / Piaggio 50cc 2T

The job of a carburettor is to supply the engine with air and fuel mixture. While there are many different types of scooter carbs, virtually all operate by the same method. Carb tuning, is the process of adjusting the various fuel and air control mechanisms within the carb to achieve the optimum fuel and air mixture throughout the rev and throttle range.

Different model carbs use different size jets and needles, to make things easier we offer this carb with the various tuning kits available. Simply add on the tuning parts you need, and you’re ready to go!

Main jets:

The job of the main jet is to increase fuelling as throttle is applied. As the slide opens, more air is supplied to the engine. To keep the fuel/air mixture correct, the fuelling must also be increased at the same rate. Installing a larger carb significantly changes the fuel/air mixture, and it must be tuned to suit. While this carb does come with a main jet installed, every scooter is different and will have a slightly different fuelling requirement. You MUST tune the main jet, failure to do so may result in engine damage. Different size main jet kits suit different applications, we have supplied a guide on the selection drop down as to what size kit is generally appropriate for each application.


Pilot Jets:

The job of the pilot jet is to supply the base amount of fuel the engine needs to run (sometimes called the idle jet). This would usually only need to be changed from the factory setting if a pod filter is being run, or if the bike has a racing cylinder installed (bridge port cylinder kit). In situations of sudden, high fuel requirement (eg, rapidly applying throttle from idle), there is a short delay in the fuel supply from the main jet. If the pilot jet is set correctly, its able to make up this shortfall from the main, allowing the engine to begin to rev until the main supply kicks in. If the pilot is set too lean, bogging will occur. If the pilot is set too rich, the engine will not rev.



The job of the needle is to moderate the supply of fuel from the main during medium throttle ranges. These are most often times where you’re trying to maintain a speed limit, on anywhere from 1/4 to 3/4 throttle. The W16 needle supplied in the kit is characteristically very rich – which results in very rough mid throttle range, where the bike will only run cleanly on full throttle. Installing a leaner needle restricts the fuel supply from the main at medium throttle ranges, allowing the fuel/air mixture to be more consistent through the throttle range, and much more pleasant riding experience.

Additional information

Main Jet Kit

Include 50 – 72 Jet Kit (to suit most 50cc), Include 75 – 98 Jet Kit (to suit 70cc with airbox), Include 100 – 122 Jet Kit (to suit 70cc with pod filter), No Thanks, I Don't Need Jets!

Pilot Jet Kit

Include a 30 – 52 Pilot Jet Kit (Necessary for use with a Pod Filter), No Thanks, I Don't Need Pilot Jets!


Include a W Needle Kit (Suitable for all applications, for smooth throttling), No Thanks, I Don't Need Needles!

Fitment List

  • Aprilia
    • Scarabeo 50 with Piaggio engine (2-stroke)
    • Sportcity 50 One (2-stroke)
    • SR 50 R (since 2005)
    • Mojito 50 Custom (2004-)
    • Mojito 50 (2004-)
    • SR Motard 50
  • Derbi
    • GP1 Racing 50
  • Italjet
    • Dragster 50
    • Millenium 100
    • Torpedo 50 with Piaggio engine
  • Piaggio
    • Liberty 50 (2-stroke)
    • NRG 50
    • Typhoon 50
    • Typhoon 50 New (2-stroke since 2010)
    • Zip 2 50
  • Vespa
    • Vespa ET2 (since 2000)
    • Vespa LX 50 (2-stroke)
    • Vespa LX 50 (2-stroke) FL (2009)
    • Vespa S 50 (2-stroke)
    • Vespa LX 50 Touring (2-stroke)