Gearbox complete (gears incl. main shaft + auxiliary shaft) -BGM PRO Original- Vespa Smallframe, 4-speed- 58, 54, 50, 46 teeth, Vespa PK, ETS, V50 (V5A1T, 69444-), Special (V5B3T, 94315-), Elestart (V5B4T, 1514-), PV125 (VMA2T 150203-), ET3 (VMB1T, 8161)

bgm PRO Gearbox for Vespa Smallframe with Original Ratio

Completely assembled and precisely shimmed gearbox – ready to install.
Gear ratios as original.
Shorter, sportier ratio possible by simply changing the secondary shaft (see accessories).

Extremely durable gearwheels made of high-grade steel

The gearwheels are manufactured in Europe from high-alloy NiCrMo case-hardened steel (14NiCrMo13) to withstand the highest loads.
The precisely machined high-quality base material is then hardened at Thyssenkrupp, making it ready for extreme engine performance. To ensure this, BGM gearwheels undergo extensive testing.

Widerstandsfähiger als originale Piaggio Zahnräder

TEST LAB
Pulsation tests in a German test lab, comparing very robust original Piaggio gears with our BGM prototypes, showed a 90% higher load capacity for BGM gears. The precisely defined surface hardening to 58–60 HRC also makes the pinions extremely resistant to wear. Better than Piaggio parts. Always consistently high quality. No compromises.

Flexible application & suitable for many Vespa Smallframe engines

APPLICATION
Suitable for all types of use, whether touring or racing.
The gear ratios exactly match original Piaggio gears. Additionally, a shorter fourth gear is available. The gearwheels are compatible with all commercially available secondary shafts that are approved for use with standard gearbox parts.

GEAR TYPE 42
BGM PRO gearwheels correspond to the latest version introduced by Piaggio from 1976 onwards. Commonly known as the PK gearbox, it was already used in ET3 models and the V50 Special. Original gears of this type are identified by an embossed number/letter combination. PK-type gears start with '42' and end with '/s'.
BGM PRO gearwheels therefore also carry the '42' marking.

Special features of Gear Type 42 & conversion notes

COMPATIBILITY
BGM Pro gearwheels fit all engines originally equipped with this gearbox type or already converted to it. For converting older engines/vehicles (pre-1976), no new main shaft is required. Only the gearwheels and the PK-type selector cruciform (height = 50 mm).

3-speed conversion
3-speed engines can also be easily converted to a 4-speed gearbox using the appropriate 50 mm high selector cruciform and BGM Pro gearwheels.

Austrian gearbox
Austrian mopeds have a longer secondary transmission.
Here you can convert to the BGM Pro gearbox if the secondary shaft is also replaced. This gearbox was also used in vehicles for other markets (e.g. Portugal).

Exceptions
Vespa V50 1st series (V5A1T) with 1st series engine (V5A1M up to engine number 92876): These engines have a narrower engine casing and a narrower main shaft. Conversion is not possible here.

CONCLUSION: Very robust gearbox components with excellent value for money!