Does anyone know what these 'springs' are called?

Torsion springs?

All normal coil springs are torsion springs. These are not normal coil springs, their action is more cantilever, like a coiled up leaf spring.

Just folded so they actually provide torque rather than linear force, But the metal is not in torsion. Which is how was taught the definition of a torsion spring is - so a torsion bar is the basic one, if you coil that up you get a coil spring , but the metal is still being twisted. The other type of spring is where the metal is being *bent*, not twisted, its a cart spring or cantilever spring, and if you coil THAT up you get what's in those images.

Yes, thanks. That does seem a common term for them. The normal suspects such as eBay don't stock them unless I buy from China with a corresponding delay in delivery.!

I can't tell what size they are, but non-critical springs are easy to make using a suitable mandrel and piano wire. You'll probably find several relevant YouTube vids. Alternatively, if they're critical, search for a custom spring maker - this chap has been helpful in the past: Marius Smith snipped-for-privacy@springmakers.uk.com>

(No connection, YMMV blah blah blah)

What size, and what application do you have in mind?

Hairpin Springs.

Ping-Fuckits (where are my bloody glasses)

When working on car drum brakes I tied a piece of string to the spring and attached the other end to the car chassis/body before removing springs. This was after a incident when a spring went flying off into the blue yonder whilst servicing the brakes on a Mk3 Ford Cortina :)

There’s a pic of a stripped-down 1948 Velocette KTT Mk VIII engine here, and you can see the hairpin valve springs.

My brother had one of these, but it being against my parents wishes, he garaged it at a friend’s place so I never got to see it.

Apparently, it was made road legal with an extensive kit comprising bicycle battery lights front and rear, and a saucepan lid with holes drilled in it over the end of the megaphone.

Now apparently worth north of £35,000…

I had one with a bronze cylinder head.

What did you think of the bike?

Back in the day I rode mainly Velocette: two Noddy bikes, a MAC, and two Venoms (one of which was a MkI Clubman).