
Original: $199.00
-65%$199.00
$69.65The Story
A forged aluminium piston kit designed as a standard-compression replacement for the 95.00 mm standard bore, with a size grade C piston to match Yamaha’s A/B/C cylinder grading. The piston features a hard-anodised crown and MOS2-coated skirt, and is supplied complete with piston rings, wrist pin and circlips for reliable service.
Features
- Forged aluminium construction for strength and durability
- Hard-anodised crown to resist heat and carbon build-up
- MOS2 (moly) skirt coating to reduce friction during running-in
- CNC-machined dome for consistent volume and finish
- Supplied with piston rings, wrist pin and circlips
- Size grade C to match Yamaha cylinder grading
Specifications
- Manufacturer part number: FX-40045-C
- Bore size (nominal): 95.00 mm (standard)
- Piston diameter (grade C): 94.97 mm
- Compression ratio: 12.5:1 (standard)
- Application: Single-cylinder, four-stroke
- Components included: Piston, ring set, wrist pin, two circlips
Cross-Reference OEM Part Numbers
- 5TJ-11631-00
- 5TA-11631-00
- 2S2-11631-20
Vehicle Fitments
-
Yamaha YZ450F 2003–2009
Description
A forged aluminium piston kit designed as a standard-compression replacement for the 95.00 mm standard bore, with a size grade C piston to match Yamaha’s A/B/C cylinder grading. The piston features a hard-anodised crown and MOS2-coated skirt, and is supplied complete with piston rings, wrist pin and circlips for reliable service.
Features
- Forged aluminium construction for strength and durability
- Hard-anodised crown to resist heat and carbon build-up
- MOS2 (moly) skirt coating to reduce friction during running-in
- CNC-machined dome for consistent volume and finish
- Supplied with piston rings, wrist pin and circlips
- Size grade C to match Yamaha cylinder grading
Specifications
- Manufacturer part number: FX-40045-C
- Bore size (nominal): 95.00 mm (standard)
- Piston diameter (grade C): 94.97 mm
- Compression ratio: 12.5:1 (standard)
- Application: Single-cylinder, four-stroke
- Components included: Piston, ring set, wrist pin, two circlips
Cross-Reference OEM Part Numbers
- 5TJ-11631-00
- 5TA-11631-00
- 2S2-11631-20
Vehicle Fitments
-
Yamaha YZ450F 2003–2009




















