I cannot say with authority what they were originally on these models (Hence joining to ask & learn) but in my experience with a wide range of vintage bikes they are in this instance nearly 70 years old and any number of petrol taps and fittings could have been installed.
I can take some photos of some I have in stock, but BSA tended to use a different type than the typical Triumph. Many are push pull, but I have some that are also lever action and some, have 2 positions on the tap, one for regular and one for reserve. The tap has 2 feed pipes at differing lengths. BSA tended to use a larger bung fitting in their tanks for both single taps and dual taps as well and I try to keep in stock brass adapters as for a rider, I use a repop ewarts style tap instead for anything thats a rider and not a show bike. (Rivet counter angst). I have had challenges getting some of the original taps to work properly in useage without leaks or mishaps. A static display bike does not have these issues.
The original taps in many cases used a cork seal internally and of course these are prone to leak when they dry out. The repops use Brass and viton and much more durable. I have seen a few that were simply well machined brass fittings and refurb was lapping them in with grinding paste. As noted, some bikes use a double banjo on the carb(S) or a T fitting so when using double taps you get fuel from both sides and in dual carbs, to both carbs. But not all bikes do that. The challenge when doing restorations is also getting leak proof joints and many of the originals used a crimped metal cup on the fuel lines. IMHO these are a PIA and very prone to leaking once installed and then disturbed at a later date. I use often times modern fuel injection type full width stainless worm clamps that look very similar to original fittings.
Modern fuel as well is hard on fuel lines and bits. Avoid alcohol-sugar water fuels if you can,, but I have been using a German car fuel and oil line with a cloth covered weave exterior that seems to hold up well... I think we got the last batch from a NAPA warehouse and was BALKAMP brand, but need to source more of this and looking into it. The clear tubing just does not seem to hold up anymore to modern fuels and is a source of constant problems. I have built a few very early machines and customs using Copper tubing. The coils and finish is very cool and steam punkish, but in reality, copper work hardens and challenging to work with and in application with vibration the same result, metal fatigue, cracking and leaks. But it DOES look super cool.
I have a wide selection of fiber sealing washers and some work well, but not always. Triumph/BSA in early 1970s switched to a Stainless AN washer and a bi-metal sealing washer with a Nitral O-Ring on the ID. Any time I can, I upgrade to these types. They work really well.
When fitting a reserve type tap to a bike, I made it a practice of the following,. Right side is reserve. R=Reserve (easier to remember) (Assuming the tank is symmetrical ) On some taps the reserve has a R on them but not common, Sometimes I will also drill a small hole in the lever that actuates reserve. This serves as a physical and visual cue as well its reserve. This is my own little quirk, but the reality is own a lot of machines as well as access to many others or past shop work. My memory was poor before, but now I have memory issues all the time so LABEL LABEL LABEL. Sure beats struggling to reach a lever and try to remember which one when sputtering along and a large 18 wheeler or SUV bearing down on you out on the road.
Ill dig out my petrol tap collection this week..and post up a topic on this. Some of them I would be very interested in group feedback on what they are and proper applications. If it can be used as a reference for others that would be cool.
That exhausts my knowledge on this topic
