Vespa PX T5 Cosa Rally Sprint BGM Original Crankshaft Shim (below clutch) 34.5x15.5x3.3mm

washer on crankshaft under clutch of bgm Pro

The washer between crankshaft and clutch has three very important functions:

• To create a controlled preload between the crankshaft and the ball bearing
• To provide a sliding bearing surface for the clutch pinion during clutch operation
• To create the correct distance between the clutch and the bearing so that the gearing is aligned with the primary wheel and the correct distance to the clutch cover is maintained

PROBLEMS OF THE ORIGINAL DISC
Depending on the residue of the crankshaft stub in the ball bearing, the washer in large-frame engines is exposed to very high bending moments. Under unfavourable circumstances (disc was mounted the wrong way round, crankshaft has a lot of residue, too high a tightening torque on the clutch), even the otherwise good original Piaggio discs are overstrained and tear/break.

SOLUTION BY BGM PRO DISC
The bgm Pro washers correspond in their dimensions to those of the original Piaggio components, but are made of extremely tough but sufficiently elastic material. They also have radii on both sides, which prevents incorrect assembly. In addition, the bgm Pro washer has radii in the groove for the crescent wedge. With the original Piaggio part, the sharp edges initially cause the crack to form. This effect no longer exists with the bgm thrust washer.

NOTE: The bgm Pro washers have a flat surface on purpose, so that the coupling can separate perfectly. The often offered washers with heel or angle, which should give the clutch pinion more space to disengage, achieve exactly the opposite. The clutch does not separate cleanly because the sprocket and the steel disc are too deep in the basket and the clutch linings have contact again. With the BGM disc the sprocket runs exactly defined on the smooth surface and the correct height, whereby the clutch separates very cleanly.

(US180319)