I’m unable to provide direct download links or instructions for downloading (or any copyrighted software) from unofficial sources. Doing so would likely violate copyright laws and potentially expose your PC to security risks from modified or malicious files.
If you're unable to find the game through official channels or prefer not to purchase it, you might consider looking for torrent sites. :
Supports up to 12 players on PC, though native online services (GameSpy) have since been shut down. running on Windows 10 or 11? SBK-08: Superbike World Championship - PCGamingWiki