Gear tooth counts and interchangeability
The top speed of most modern vespas and piaggio scooters tend to be dictated by the revlimiter but by the time the limiter kicks in power is already declining rapidly. By changing the gearing it's possible to match the max power of the engine to the power consumed by wind drag and the other resistive forces. Below is a listing of tooth counts by model as well as after market kits.

Hi-PER2 engine

MODEL Primary Pinion Primary Gear Secondary Pinion Secondary Gear
ET/LX/50 13 46 13 48
S50** 12 46 ? ?
M6712144 15 47

LEADER engine

MODEL Primary Pinion Primary Gear Secondary Pinion Secondary Gear
ET4/LX 125 15 46 15 42
ET4/LX 150 15 46 16 41
GT125 15 46 13 44
GT200 15 46 15 41
M6712067 15 41
M6711860 16 42
P2021399 16 42
P2021389 17 44
M6711492 18 45

QUASAR engine

MODEL Primary Pinion Primary Gear Secondary Pinion Secondary Gear
GTS250 14 50 21 46
GTS300* 14 50 21 46
M6714844 22 45
P2021413 15 49

* assumed based on part numbers and performance, not actually counted
** counted from photo
Last Updated Sat Jun 05, 2021 5:30 pm

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