Tuning set for carburetor -BGM PRO for Vespa PX125/150 with BGM PRO 177 cylinder kit- main jet set, secondary jet, mixing tube, main air correction jet

BGM PRO tuning set for Vespa PX125/150 with BGM177 cylinder and SI carburetor

CARBURETOR TUNING SET BGM177 FOR DELL'ORTO SI20/20D, SI24/24E, SI24/24H, SI26 WITH STANDARD AIR FILTER

The BGM177 is an easy cylinder to tune due to its linear power development. It provides clear feedback as to whether the engine is running too lean or too rich. This set contains jets with which a clean basic tuning of the engine with an SI series carburetor is guaranteed.

The tuning set relates to a conventionally constructed engine with BGM177/187 and a so-called box exhaust system. We recommend the BGM BigBox Touring or the Polini Box due to their perfectly matching cylinder characteristics. With its harmonious torque curve, the engine can be tuned quickly and easily. It requires no dynamic ignition adjustment or other special carburetor modifications. In general, however, you should take a few hours for a good basic tuning of the engine.

SCOPE OF DELIVERY

• Main air correction jet: 160

• Mixing tube: BE3

• Hauptdüsenset: 115-118-120-122-125-128-130-132-135-138

• Secondary nozzle: 55/160

The scope of delivery of the jet set is based on the basic jetting of the SI24/24E carburetor of the PX200 models. The jetting is already very close to the ideal for a well-running engine and only requires a slight upward correction in the main jet area (larger main jet). Anyone using an SI24 carburetor on the BGM177 therefore usually already has a very good basic setup and only needs a main jet set (exception: carburetor of the German PX200 models with 10 hp cylinder. Here, a 190/BE4 air correction/mixing pipe combination was used ex works. Please replace these with the components included in the set). The BGM Faster Flow carburetors with 24/26 mm also use the good basic setup of the PX200 models with 12 hp.

AIR FILTER
The jetting requirements of the engine are heavily dependent on the air filter used. The standard air filter does not look particularly powerful, but it is not a throttle. There is therefore no need to replace it with a funnel, venturi or even omit it altogether. The SI carburetor reacts very sensitively to changes in/on the air filter, which is why it should be retained for a good basic setup and not modified. The underside of the air filter has a heart-shaped recess. When fitted, this sits above the jets of the carburetor. It is often recommended to drill it out or even remove it completely. This has a very large influence on the mixture formation and can quickly lead to dangerous leaning. Changes should not be made in this area at the beginning.

Note: There are standard air filters which already have two holes (Ø6+Ø8mm) ex works. These filters come from the Vespa Cosa models, which have a second air filter and therefore completely different requirements for mixture formation. If possible, replace this filter with the closed type from the PX models.