This Wossner forged piston kit with a 99mm bore (actual 98.96mm) is designed for BMW 1100 and 1150 series motorcycles, including RS, GS, and S models across all production years. Engineered for durability and precise combustion performance, the kit includes two pistons and meets OEM compression specifications.

Features

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  Forged construction for enhanced strength and heat transfer

  
  


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  Elliptical design distributes loads evenly under thermal expansion

  
  


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  Manufactured in Germany for high performance and reliability

  
  

Specifications

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  Bore Size: 99mm (actual 98.96mm)

  
  


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  Stroke: 70.50 mm

  
  


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  Clearance: 0.04 mm

  
  


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  Display Displacement: 1085 cm³

  
  


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  Wossner Compression Ratio: OEM

  
  


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  OEM Compression Ratio: 10.70:1

  
  


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  Dome Volume: +2.30 cm³

  
  


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  Compression Height: 32.10 mm

  
  


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  Lock Part Number: C22X1.6

  
  


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  Pin Part Number: WP009

  
  


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  Ring Set Part Number: 990XSY

  
  

Vehicle Fitments

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  BMW 1100RS (All years)

  
  


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  BMW 1100GS (All years)

  
  


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  BMW 1100S (All years)

  
  


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  BMW 1150RS (All years)

  
  


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  BMW 1150S (All years)