Wossner Forged Piston Kit 68.50mm Bore – Yamaha YZ250 / WR250 (1988–1991)

This Wossner forged piston kit is designed for Yamaha YZ250 and WR250 models from 1988 to 1991. With a bore size of 68.50 mm and a piston diameter of 68.44 mm (+0.50 mm oversize), it is crafted for 2-stroke engine setups requiring improved strength and thermal efficiency. The forged aluminium design and elliptical geometry ensure even load distribution and effective heat transfer, reducing wear and the risk of piston failure. Manufactured in Germany for dependable performance.

Features

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  Forged construction for superior durability and strength

  
  


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  Optimised design for combustion chamber heat transfer

  
  


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  Elliptical shape promotes balanced load distribution under thermal expansion

  
  


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  Precision-engineered in Germany

  
  

Specifications

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  Bore Size: 68.50 mm

  
  


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  Piston Diameter: 68.44 mm

  
  


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  Engine Displacement: 246 cm³

  
  


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  Stroke: 68.00 mm

  
  


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  Clearance: 0.06 mm

  
  


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  Compression Height: 36.00 mm

  
  


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  Compression Ratio: 2-stroke (Wossner and OEM)

  
  

Cross-Reference Wossner Part Numbers

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  Piston Kit: 8134D050

  
  


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  Lock: CW18

  
  


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  Pin: WP033

  
  


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  Ring Set: RSB68500 x 2

  
  

Vehicle Fitments

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  Yamaha YZ250 (1988–1991)

  
  


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  Yamaha WR250 (1988–1991)