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MCB Stage-1 Top End Rebuild Kit Yamaha YZ 85 2019-2024

Wossner /Pro-x Top End Piston Rebuild Kit

MCB Stage-1 Top-End Rebuild Kit for 2019-2024 Yamaha YZ85 . This engine rebuild kit includes a Wossner Premium Forged Piston /Pin 8104DA, Genuine Riken rings, clips and Top-End Gasket Kit. Everything you need to service your MX Top-End.

MCB offers three pistons for this model YZ85, Single and Dual Ring forged Wossner or Single Ring Cast Pro-X piston. Single ring pistons are designed more around competition racing and have slightly less drag, making slightly more HP. Single ring pistons will have to serviced more often as compared to a Dual Ring design which is intended more for trail riding and longer duration rides while also providing a longer serviceability intervals.
Single or Dual Ring Piston

Need a cylinder? Click on suggestion below or see SKU# 23431323
Need a complete engine rebuild kit? See SKU#23431322
Pricing: $139.95

Customize Your Item

- Select Your Piston -
 * required
- Single or Dual Ring Piston -
 * required
- Choose your piston size -
 * required


MCB uses Wössner pistons exclusively in all our MX/Off road kits. Germany's finest aftermarket forged piston manufacturer with over 25 years of experience in the Powersports / racing industry.

Wössner is currently the piston of choice for Monster Energy Star Yamaha Racing Team

Pro X pistons are the premier cast piston made from a specialized low-expansion, low-friction aluminum alloy, commonly used by OEM engine manufacturers to give the piston an incredibly low co-efficient of friction.

Prox Racing Parts is official technical sponsor of the Monster Energy Pro Circuit Kawasaki team


  • 23430961
  • 23430961
  • Yamaha
  • New

Shipping Information

  • Item Requires Shipping
  • 4.0 lbs.
  • W12.0000” x H9.0000” x L6.0000”

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