Gear Selector BSG "4-gear PK"
for Vespa 50 S 3°/Special V5B3
-4T 2°/SR (D)/100 2°/125 PV
Ø 50,2 mm, hardened, round,
Alongside Falc, Quattrini and Co. BSG offer some of the hottest tuning parts available to date. The three letters that make up the company name originate from the surname initials of high-end tuner Fabio Begani, racing legend Stefano Scauri and ET-3 wizard Alessandro Graiani. We could stop explaining right here because these guys don't do things by halves. Quite on the contrary BSG and the BSG supported pilots belong to the premier league of Italian scooter racing. Be it in the VPI (Vespa Pista Italia), the CIA (Campionata Italiano Accelerazione) or the new POLINI Cup. With a stunning performance of 48PS, the BSG smallframes was the most powerful scooter on the dyno at the Customshow in Landsberg 2013. It's clear that special components are required to rein such power.
If, while drag racing, you reach speeds of up to 136 kph when passing the 150m mark, then you will probably have already destroyed the odd gear selector. To prevent this BSG have included a reinforced Vespa PK gear selector in their motor that can survive power outputs of around 30 PS. The special steel used in its construction is called 18NiCrMo5 and is mostly only used for Moto GP components. Its surface is then exposed to an extensive finishing process for added durability. The mechanical tolerance between the gear selector spider and the shaft itself has been decreased to reduce the gears jumping out during acceleration. The selection process also becomes more precise. This gear selector, with a diameter of 50.2mm, can be used in combination with any of the existing PK shafts although the use of the BSG version is highly recommended.
Conclusion : If you have more than 30 PS available you cannot go wrong with this part.
SIP-TIP : Do not forget to order fresh gearbox oil and a mounting tool (part no 63791000) to make the assembly of the selector, springs and ball bearings much easier. Be careful to measure and adjust the clearances between the gear cogs as exactly as possible for an effective result.
OEM Numbers (for the purpose of comparison)