I'm referring to the time limit applicable to you, the human being, within the Schengen area.

Go do some research on your own! Start here: Wikipedia - Schengen Area to learn what the Schengen Area concept is. Once you understand the concept, go to the US State Department website Travel.State.Gov and look up the entry requirements for the countries you plan to visit. I am assuming you are travelling on a US passport.

As for your motorcycle, the basic principle that applies to any vehicle brought into a different country for tourist purposes (could be you riding up into Canada for a visit, this isn't Europe-specific) is that the tourist vehicle is admitted without duty, taxes, need to re-register it, etc. as long as it is being used by the tourist, and on the condition that it is removed from the country at the same time the tourist leaves.

Michael