The Athena standard bore cylinder kit is designed for Yamaha YZ 450F and WR 450F 4-stroke models, providing a complete top-end rebuild solution that maintains original engine geometry, displacement, and operating characteristics. Supplied with a cylinder, forged piston, wrist pin, circlips, and full gasket set, the kit ensures OEM compatibility and reliable performance under demanding riding conditions.

Features

• 
  

  Complete top-end rebuild kit for Yamaha 450 cc 4-stroke engines

  
  


• 
  

  Maintains standard bore and original engine configuration

  
  


• 
  

  Direct replacement compatible with OEM components

  
  


• 
  

  Plug-and-play installation with no modifications required

  
  

Specifications

• 
  

  Bore diameter: 97 mm

  
  


• 
  

  Displacement: 450 cc

  
  


• 
  

  Cylinder material: high-silicon aluminium with wear-resistant coating

  
  


• 
  

  Piston type: forged, CNC-machined

  
  


• 
  

  Piston coating: molybdenum disulphide

  
  


• 
  

  Head gasket type: multi-layer steel (MLS), stainless steel, laser-cut

  
  


• 
  

  Kit contents: cylinder, piston, wrist pin, circlips, gasket kit

  
  


• 
  

  Part number: P400485100107

  
  

Vehicle Fitments

• 
  

  Yamaha YZ 450F (2023–2026)

  
  


• 
  

  Yamaha WR 450F (2024–2026)