A adv trip can be so many things, and for all the first trip ss a milestone. My first "road trip" was a nearly 8000km long trip in the U.S. on a HD Heritage in 2007: http://jarleeekroute66.wordpress.com/
A year later it was a long trip here in Norway on a Kawasaki VN800.
In 2011, I drove with my daughter a trip through 17 countries on my Yamaha XV1700 Road Star Warrior http://europatur2011.wordpress.com/
and in 2012 I ran the distance Norway - Turkey on the same bike. A ride on 12100km http://jarleeeknorgetyrkia.wordpress.com/
If you drive on dirt roads or asphalt, I think that all motorcycle brands can be used, but you may need to add a route on which brand you choose, and what skills you have as a driver.
For my own part, I have driven motorcycle in 10 years and is fully aware that my skills are far below what the skilled drivers can manage. But it prevents me not to look forward to the next trip :-)
I am glad to have joined this forum and hope to get lots of useful information and inspiration for future trips. The goal is 3 month trip.