1. Use MixFile Remixer to extract hsbk.mix from your BIKES folder located in your C:\Program Files (x86)\RIDE\BIKES .
2. put BIKE400.dds in BIKES\MSBK\BIKE400 folder where you've extracted hsbk.mix
3. Repack hsbk.mix then copy hsbk.mix back to C:\Program Files (x86)\RIDE\BIKES folder.
Here is a video of the bike