How did the dirt bike transform over the years?

Dirt bikes draw their origin from scrambling contests in the United Kingdom at the start of the century, where early motorcycles were raced along trails. These racers eventually started to adapt their bikes to cope with the terrain, the factories caught on to the act and started introducing motorcycles to cater for these people, with longer travel suspension, lighter stiffer frames and so on. Scrambling eventually evolved into trial and enduro rallies and became a worldwide sport, culminating in the ISDT(now the ISDE). All the different factories started competing against each other.

The first major transformation of dirt bikes was the introduction of effective suspension, front and rear. The next major breakthrough was the advent of expansion pipes for two stroke engines which virtually eliminated the four stroke thumper from most types of competition due to it's better power, lighter weight and simple design.

Dirt bikes continued to evolve over the years gradually getting more powerful, lighter, with better suspension and increasing reliability. Eventually mono-shock rear suspension replaced dual shock rears and the bikes became more specialised for the type of competition they were used for, trials, Motocross, enduro, desert racing or just trail riding.

Rule changes in competition meant that two-stoke bikes had to compete with four-strokes almost twice their size. This brought about a resurgance in fourstroke motorcycles which seem to have turned the tables.

Aluminium frames replace the steel frames that were common less than a decade ago.

The latest development is the introduction of fuel injected engines over carburated engines.