Description
Top-end bearing wear is one of the most common culprits behind loss of compression and reduced engine efficiency in high-mileage sleds. The Wiseco B1039 is a direct OEM replacement engineered to restore full bearing function and prevent catastrophic piston seizure during aggressive acceleration. If you’re rebuilding your Polaris 440 Pro X, this bearing is non-negotiable for reliable performance.
Built from premium high-silicon aluminum alloy with case-hardened surfaces, this bearing delivers the precision fitment and durability required for sustained high-RPM operation. Installation is straightforward during a standard top-end rebuild—no machine work needed.
- Fitment: Polaris 440 Pro X (2001–2003)
- Dimensions: 20 x 25 x 21.8 mm
- Material: High-silicon aluminum alloy
- Case-hardened construction
- Precision-engineered tolerances
- Optimized for high-RPM operation
- Reduced friction design
- OEM-equivalent quality
- Bolt-on installation
- MPN: B1039
