Sorry, didn't check Adv rider as often as I used to. You can rent dirt bikes here for some fun on their track:
http://www.mxclub.com.hk/
Not much places to do adv style rides here in Hong Kong and there's no companies renting out bikes for sure unless you trick a dealer into giving you a test ride LOL
I ride with a group on Sundays we meet up in Ma On Shan's Shell station 7am sharp and do the Route Twisk aka Tai Mo Shan and Luk Gang breakfast routine.