PISTON KIT 27 YAMAHA YZ 250 F PROX 76.95mm 77.00mm BORE 14.1:1 FORGED D05-11631-00 01.2437.A

The ProX piston kit is intended to replace the piston in a Yamaha YZ 250 F engine during a top-end rebuild. Its dimensions and compression ratio are listed below to help confirm the required piston size.

Specifications

• Standard bore: 77.00 mm


• Piston size: 76.95 mm


• Actual compression ratio: 14.1:1


• Total height: 34.30 mm


• Piston pin hole diameter: 17.00 mm


• Compression height: 11.50 mm


• Boss spacing: 16.00 mm


• Piston head: flat with raised top


• Four valve pockets


• Forged piston

Cross-Reference OEM Part Numbers

• Yamaha: D05-11631-00


• PROX: 01.2437.A

Vehicle Fitments

• Yamaha YZ 250 F: 2027