Piston -BOLLAG MOTOS made by Wössner- Vespa GS150 / GS3 (VS2T, VS3T, VS4T, VS5T) - 58.75mm (8. Oversize) | Pistons | Cylinder | Engines

Preview: Piston -BOLLAG MOTOS made by Wössner- Vespa GS150 / GS3 (VS2T, VS3T, VS4T, VS5T) - 58.75mm (8. Oversize)

Description

High quality forged piston BOLLAG MOTOS exclusively manufactured by Wössner in Germany.

These pistons are exclusively manufactured by Wössner in Germany. Thin piston rings and modern C-Clip piston pin locks ensure the highest quality and durability.
The pistons are machined from forged blanks.

Ideal for the original GS150 cast iron cylinder, which has already been bored several times.
The standard bore of the GS150 models is Ø57.00mm.
The oversizes Piaggio could deliver from the factory are always 2/10mm bigger than the previous size, based on the stock bore:

Oversize Piaggio:

1.oversize 57.2mm
2.oversize 57.4mm
3.oversize 57.6mm
4.oversize 57.8mm

The smallest dimension of the Bollag/Wössner pistons is 58.00mm.
This corresponds to the 5th oversize.
Therefore these pistons are ideal for cylinders that have already been ground several times.

Oversize Bollag/Wössner:

5.oversize 58.00mm
6.oversize 58.25mm
7.oversize 58.50mm
8.oversize 58.75mm
9.oversize 59

.00mm

The dimensions always refer to the grinding dimension of the cylinder (a 58.0mm piston is always slightly smaller and therefore suitable for a cylinder with Ø58.0mm bore etc.).
Piaggio specifies in the workshop manual as piston running clearance 0.075mm (measured with 115° lateral offset and 15mm clearance to the piston pin axis).
In the workshop manual the dimensions are mixed up with the tolerances for the pistons of the GS160 (VSB1T), where the dimensions are given with 0.12mm according to the Italian measuring method (5mm below the piston ring zone).
Ralph Bollag recommends a piston running clearance of 0.11-0.12mm (11-12/100) for his forged pistons, which basically require a somewhat larger running clearance.

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