It is rare for bikes built in back garden sheds to become a marque in their own right, but this is just what happened with the eclectic mix of Triumph engines and Norton frames which became known as Tritons.

Tritons were a bike of their age - but some 40 years later new versions of this most famous "special" are still being created. The idea behind the Triton was simple. Put a powerful, pre-unit construction Triumph engine into a Norton "Featherbed" frame and you had a fast, affordable bike equal to any of the mass-produced machines on sale at the time.

Originally, cost was a major influence on the popularity of Tritons. In 1965, a good Triumph engine taken from the ill handling T110 cost £30. Another £30 bought a complete Norton Model 50 or ES2 in rough condition. The Norton provided not only the frame but the gearbox, clutch, suspension and brakes. Now the fun could begin.

If you knew someone at any one of the many British aircraft manufacturers then, a fiver bought a set of alloy engine plates which enabled the Triumph engine to mate with the Norton frame. Shipbuilders Cammel Lairds and Vickers were favorites for stainless bits made at lunchtime. It's no exaggeration to say that the British defence industry produced some of the finest Triton parts ever made.

Depending on how exotic the finished product was going to be, maybe second-hand petrol and oil tanks taken from a genuine Manx Norton racer found their way on to your bike. Manx seats were also highly desirable but if these weren't on the menu then fiberglass replicas were abundant.

Clip-on handlebars, a chromed headlamp and rear-set footrests were essential formal dress for any self-respecting Triton. Swept-back exhaust pipes terminated in silencers that looked gorgeous - and had nothing to do with reducing noise.

There was no "right" way of making a Triton. The bike could be as exotic or basic as the builder wished, but the best Tritons were truly spectacular. Milled engine plates, a plethora of Manx parts and highly tuned Triumph engines resulted in a finished product which was better than anything which could be purchased from a manufacturer - British, European or Japanese. These Tritons were 130-mph road-going racebikes with genuine track quality, speed and handling.

In fact, so good were the top Tritons that British builder Dave Degens won the Barcelona 24-hour race in 1965 and 1970 on bikes he had constructed himself.

At the other end of the scale, words cannot describe how dire a job some backyard constructors made of their Tritons. Next time you see a picture of a 1960s "Rocker" outside his favorite cafe, have a look at his Triton. That apparently huge front brake is simply a fake alloy pressing held on with wire and those clip-ons are so low down the fork leg that they might as well be extensions to the wheel spindles. These Tritons were even dangerous standing still with the engine stopped!

But these aberrations do not detract from either the aesthetic quality or riding appeal of a well-built Triton: Even today, classic bikes don't get any better.