I confess that I don’t know much about these but either way this is a cool build.. Nice blog also! Check it out!
Hi,
Greeting from Indonesia
Great blog..
I just want to share one of my friend’s bike
He built it a few years back,
a 1992 Yamaha RX-Z converted to a dirt bike
Cheers
DariztDesign
www.dariztdesign.blogspot.com
Motorcycle Photo Of The Day 
Looks to me like that has been converted to an observed Trials bike, not a dirt bike, to be specific.
You’re correct of course but I generally use the term “dirtbike” very broadly.