This Wossner forged piston kit is designed for the 1997 Yamaha YZ125 and features a 54.00mm standard bore. Manufactured in Germany, it is built to deliver structural integrity and efficient thermal performance in high-revving two-stroke engines. The elliptical piston design ensures uniform surface contact under heat expansion, preventing localised stress and reducing the risk of piston collapse. The kit is optimised for effective combustion heat transfer to the cylinder wall, supporting engine reliability.

Features

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  Forged piston construction for high mechanical strength

  
  


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  Elliptical profile ensures consistent expansion and even load distribution

  
  


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  Reduces risk of structural failure under thermal stress

  
  


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  Promotes efficient heat transfer from the combustion chamber

  
  


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  German-engineered for precision and durability

  
  

Specifications

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  Bore Size: 54.00mm (Standard)

  
  


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  Actual Diameter: 53.94mm

  
  


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  Compression Height: 28.00mm

  
  


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  Stroke: 54.50mm

  
  


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  Displacement: 124 cm³

  
  


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  Piston Clearance: 0.06mm

  
  


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  Compression Ratio: 2-stroke (Wossner and OEM)

  
  

Cross-Reference OEM Part Numbers

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  Wossner Piston Kit Part No: 8117DA

  
  


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  Lock: CW15

  
  


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  Pin: WP032

  
  


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  Ring Set: RSB5400

  
  


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  Rod: P2019

  
  


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  OEM Reference: 4XM-11631-30-A0

  
  


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  Cross Reference: 693M05400

  
  

Vehicle Fitments

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  1997 Yamaha YZ125