What: A motorbike, registration number 190, which I guess makes it the 190th motor vehicle registered in the colony. Do we have any motorbike historians reading, who can tell us what model we're looking at?
The white suit is an interesting choice, given the oily nature of an old motorcycle!
There's also a poster on the pillar, advertising a film called "The Claw"  showing at the Hong Kong Theatre :
When: Here's the back of the photo, dated 18th October, 1920:
Where: Probably somewhere in Central, not too far from the Hong Kong Theatre. The theatre was in the old Land Office building, where the corner of Queen's Road and Theatre Lane is today.
Looking at the back of the card again, it says the photo was taken in front of the office of ... then I struggle to read the writing. A couple of clues are that the two names are the same, and the first letter looks like the "K" in "Hong Kong". Here's a comparison, with "Kong" on top, and the company name below:
Looking at the nearest Jurors' list we have , I got lucky. There's a company listed named "Komor & Komor", which matches the writing. I thought they sounded like a legal firm, but it turns out they were dealers in Japanese curios! 
The next clue is a newspaper article from 1921  reporting that Komor & Komor were going out of business, and closing their shop in the Alexandra Building. We've got a couple of photos of that building , but none with enough detail to show if there's a match in the pillar design. For now I'll assume we're looking at Alexandra Building (the Des Voeux Road side, based on the shadows).
Who: The first name looks like "George", and the second looks like the "Komor" in the company name. There's a mention of a George Komor from that company in a 1923 newspaper , so I reckon he's our man.
As always, comments & corrections welcome!
- "The Claw" starred Clara Kimball Young. It was released in 1918, so it had taken its time to reach Hong Kong.
- The Hong Kong Theatre.
- Currently the latest Jurors' List we've finished typing is the 1914 list. Can you help us type up the 1915 list?
- "Paul [Komor] moved with his parents to the Far East in 1896, when his father decided to join his uncle Siegfried Komor in a Japanese curio business in Hong Kong." from "Portrait of the Komor family in Shanghai"
- China Mail, page 4, 11 Oct 1921
- The Alexandra Building (1st generation)
- The Brisbane Courier, 11 Sep 1923