1. get your boss to put his unreasonable demands on paper or email, anything that gives you documentation of his position.
2. Put your objections on paper or email for the same reasons.
3. If he still insists that you ride it, take photos of the bike exactly as it is before you ride it, get the day's newspaper in the shots so as to document the day the pictures were taken.
4. Sue them for the 'injuries' you sustain.
5. Get a job where they at least acnowledge your status as a member of the human race