I don't know if you've noticed, but I'm a sucker for the weird and wild ways that motorcycles, UTVs, and other powersport machines are used in conflicts around the world. Not because of their lethality or the damage they do, but because of the engineering used to just make the damn things work.
I mean, there's a lot of recoil in anti-aircraft weapons, and you wouldn't think that a good gun platform would be an off-brand Chinese motorcycle. Yet, where there's a will, there's a way, and there's no better example of such backyard, Red Green-esque engineering than the technicals that folks without the US' military-industrial complex can come up with.
But even superpowers have been known to produce some weird, garage-built-looking technicals. Maybe they have a slightly better fit and finish than something Tony Stark built in a cave, from a pile of scraps, but not by much. Case in point, this motorcycle that the British Army had built in and around 1919, complete with a sidecar and what looks to be a Vickers water-cooled machine gun.
Dope.
According to the post on the sub-Reddit r/ShittyTechnicals, the OP stated that the picture was of "Two Motor Machine Gun Batteries, numbers 19 and 22, [which] served during the 3rd Afghan War (1919) and the revolt in Waziristan (1919-1920). They were equipped with Matchless, Premier, Zenith, Enfield and Clyno motorcycles, many of which were fitted with Vickers machine guns mounted on sidecars. Both units also had armoured car sections."
A motorcycle machine gun team, 1919
byu/vitoskito inshittytechnicals
As for which make and model the motorcycle is, I'm honestly not sure. The picture, though pretty dang good in detail, has a few bends and warping thanks to some odd lighting. I'm also not an expert in pre-WWII motorcycles, though I'd bet a dollar over donuts that some of you could probably figure out what it is quickly.
What I can say is that the OP was correct in that the battery looks to be using a Vickers machine gun. The weapon began production in 1912 and was water-cooled, like many other early machine guns, and was chambered in .303 British (7mm) and required the three men you see in the picture above. It needed that many people to operate as one person to fire, one person to feed the belt, and another to carry extra ammo, parts, and fix the thing if it broke.
Though, apparently, it was pretty reliable.
The Third Afghan War, as the OP put it, was the Third Anglo-Afghan War which kicked off in May of 1919 and only lasted a few months. The spate, between British-controlled India, and the new Amir of Afghanistan, sparked thanks to the Amir attempting to seize control over parts of India that it had prior claims to, including Peshawar and other lands near the Indus River.
But it's the motorcycle that intrigues me the most, as everything about it screams, "Yeah, I wasn't built for this!" I mean, the motorcycles in 1919 weren't exactly the most well-built, nor did they use the strongest metals around. There's a case to be made that even the motorcycles you see today running around the Middle East made in India or China are likely better gun platforms. But you gotta do what you gotta do, right?
If there's someone out there that recognizes the bike, let us know in the comments below! I'd love to learn more about them, and I'm sure our readers would too.