I was driving around town today and for I think the first time since living here I noticed that my town had a bike shop haha. I’m not motorcycle enthusiast in real life, but I checked out the shop anyways. It had a couple actual, ready to drive motorcycles but mostly it had tools and specific parts for bikes. I think it would be really awesome to see shops like these in-game.
An interesting idea, but I don’t think a motorcycle shop would be distinct enough from the existing garage to warrant its own building type.
Uh, Harley-Davidson here in the US is building all sorts of large-scale stores–good source for clothing as well, I understand. It’d be similar to a Car Dealership building. (The showroom cars will be zero-fuel!)
Garages in-game, by comparison, are repair facilities with room for two cars.
The building as outlined in the OP consisted of a bike or two and some vehicle parts. Sounds more or less like a specialty garage to me.
To be brutally honest, 0.5 brought with it a great number of new buildings that I consider little more than architectural clutter - buildings that don’t really bring anything of interest to the table, buildings that can generally be ignored, since they contain little of use that can’t be acquired more easily elsewhere. The game is beginning to collect a lot of building types that most players are likely to explore once or twice for the novelty and then never bother with again, as they rarely contain anything that justifies the time spent clearing them. I don’t think that’s a good thing, so I’ve grown a little critical of new building types.
Aside from looking different, every new building should offer an answer to two questions - how is this distinct from what’s already in the game, and what does it offer that will make people interested in exploring it?
Fair enough, and I agree that the Office Tower in particular is a serious letdown without aboveground Z-levels. If nothing else, we need to be able to move furniture around.
A $VEHICLE Dealership would probably have intact & good-condition vehicles: fuel and drive, which given the current sorry state of 100% of the vehicles found lying around in the current versions, would be a serious boon. Motorcycle dealers in particular would likely stock leathers & Helmets.
Furniture stores cold be greatly improved by allowing players to push or attach furniture to vehicles. At minimum, one ought to be able to take the armchair apart and rebuild back at base–apparently IKEA went out of business* pre-Cata. 
*He said, sitting in his POANG with ottoman. Flat-pack easy-assemble furnishings FTW.
(And office chairs IRL tend to be on wheels, no?)