Yamaha YZ 250 F (CG 39) [2017-2018] - forged pistons

PROX forged pistons for Yamaha YZ 250 F (CG 39) 2017-2018

The PROX forged piston is designed for the Yamaha YZ 250 F (CG 39) in the full 2017-2018 model year range. Its forged aluminum design combines the specified piston shape with a design for use in the 4T engine.

Function and execution

The piston's special aluminum alloy is designed to reduce friction and support reliability. The flat crown with raised top and 4 valve pockets form the verified piston geometry of this model. The execution corresponds to quality at OEM level.

Technical data

• Brand: PROX
• Piston Type: Forged
• Material: aluminum
• Diameter Ø: 76.95 mm
• Piston compression: standard 13.5/1
• Letter oversize: A
• Oversize: STD
• Rings Quantity: Set
• Stroke: 4T
• Specificity: Flat crown with raised top / 4 valve pockets

Vehicle assignment

The forged piston fits the Yamaha YZ 250 F (CG 39), built between 2017 and 2018. The specified model generation, the diameter of 76.95 mm and the markings A and STD are particularly important for the selection.

Factual note

Before making a selection, the vehicle model, year of manufacture and the technical piston dimensions should be compared with the existing engine. The standard piston compression is 13.5/1.