PISTON KIT 99-18 YZ250 1-RING, WOSSNER 8217DB 66.40

This Wossner piston kit with a 66.41mm bore (+0.01mm oversize, actual size 66.36mm) is specifically designed for Yamaha YZ250 models from 1999 to 2018. Featuring a single-ring forged design, it delivers reduced friction, reliable performance, and durability under the demands of two-stroke operation.

Features

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  Forged single-ring piston enhances response and reduces friction

  
  


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  Engineered for optimal heat transfer from the combustion chamber to cylinder walls

  
  


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  Elliptical design distributes load evenly and prevents piston collapse during thermal expansion

  
  


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  Manufactured in Germany for high precision and reliability

  
  

Specifications

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  Bore size: 66.41 mm

  
  


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  Actual piston size: 66.36 mm

  
  


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  Display (cm³): 249

  
  


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  Stroke (mm): 68.00

  
  


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  Clearance (mm): 0.05

  
  


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  Compression ratio: 2-stroke (Wossner and OEM)

  
  


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  Compression height (mm): 38.00

  
  

Cross-Reference OEM Part Numbers

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  OLD No. 56-W056.WO.B

  
  

Vehicle Fitments

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  1999–2018 Yamaha YZ250

  
  

Included Components

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  Piston: Wossner PN# 8217DB (Single ring)

  
  


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  Gasket: PN# D2041

  
  


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  Lock: PN# CW18

  
  


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  Pin: PN# WP033

  
  


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  Ring Set: PN# RSB6640

  
  


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  Rod: PN# P2028