4th gear cog -PIAGGIO- Vespa PX EFL T5 125cc, PX200 EFL (short) - 36 teeth

Fourth gear of the Vespa PX 125 LUSSO and the T5 with 36 teeth.
At the same time the SHORT fourth gear for the Vespa PX LUSSO.
This gear fits without modifications in the gearbox of the PX LUSSO, but is translated one tooth 'shorter'.
This gear wheel opens up some leeway to adapt the gearbox to sportier cylinders and timing on the 200cc engines. Because of the long reduction of the primary gearbox, it can happen that the torque is no longer sufficient to make the jump from 3rd to 4th gear.

By using this gear edge you shorten the jump and make sure that the engine can fully rev.

NOTE

: The fourth gear with 36 teeth was developed by Piaggio for the 125cc models. It was constructed from the 4-speed of the 150/180/200cc models with 35 teeth by a technique called tooth flank shifting. By this technique the gearing of the auxiliary shaft could be kept identical for all models. A disadvantage of the 36 tooth gear is however the narrower tooth base. This results when more teeth have to be accommodated on a given diameter. The narrower tooth base is of course not as stable as the 35 tooth gear, which is why Piaggio only used it in the 125cc models.

The short 36 tooth gear is however very popular with performance increased 200cc engines. With very sporty engine designs, the jump from gear 3 to gear 4 is too big and the engine no longer gets into its power band. With today's very high-torque concepts (like Malossi Sport/MHR or Quattrini M244) this tuning trick from the 1990's is still often used.

We strongly recommend to use a 4 speed with 35 teeth

.

The high engine torque together with a load peak (gear jumping, shifted etc.) can otherwise damage a 36 tooth gear. If you still need a shorter gear jump, you should realize this with another auxiliary shaft with less teeth (e.g. BGM6505 or BGM6506).

_{AI-translation}