No. You'll be a first.
You now have two choices:
1. Don't risk going to unknown lands.
2. Go and, like some modern day Marco Polo, return to report on the wonders you have discovered.
Sweet Jesus, are people so idle, scared and lacking in imagination that they really cannot find out anything about anywhere, without posting a 13 word request on an Adventure (with a capital A) motorcycle site? Here's a nice pre-made tour that'll take all the effort out of it:
http://www.mcitours.com/tours_detail_selfguided/?tourid=S06
Just by typing the single word Harz (12 words less than your appeal) into the site's Search box turned up:
http://www.ukgser.com/forums/showthread.php/405876-Louis-Moto-German-tour-routes?highlight=Harz
http://www.ukgser.com/forums/showthread.php/196668-Harz-Mountains?highlight=Harz
Typing Harz great motorcycling (10 words less) into Google, turned up:
http://biker-hotel-harz.de/en/guided-tours/ which if nothing else gives you a 'biker friendly' hotel, a guide (or at least a help with, if you don't want to be guided) the thousands of great roads to ride.
By trying this sticky (created just for bods on this site)
http://www.ukgser.com/forums/showthread.php/416452-Germany-calling
You'll be able to get with just a little effort to:
http://kurvenkoenig.de/motorrad/harz.html
With no less than 12 routes. Yes it's in 'foreign' but it's not impossible to work out.
Enjoy your holiday, mate