If you were riding dirtbikes around the turn of the century, you will know the impact the ‘new-generation’ Yamaha YZ-F and WR-F 400 and 250 models had when they launched. Until this point, two-strokes ruled the off-road world. Motocross riding featured pretty much 100 per cent premix machines, while enduro had a mix of two- and four-stroke classes, although the two-bangers continued to dominate the results.
But this all changed in 1997 when Doug Henry won the Las Vegas AMA Supercross Series final on debut, riding the prototype Yamaha YZM400 thumper, before then winning the AMA 250cc MX Championship the very next year on a production YZ400F. From that point forward, it was clear rival brands had to come up with their own competitive new-generation four-strokes to match Yamaha and stay in the game. And with that, everyone cried the writing was on the wall for two-strokes and that premix bikes were on the way out.
The four-stroke craze also took over the offroad world. In the early 2000s there were so many Yamaha WR250F and WR450F thumpers in the bush that riding areas became a sea of blue. Before long rival brands caught up and there were all sorts of high-performance four-stroke machines to choose from. Sure, some die-hards stuck with their trusty two-strokes, but for a while there they were seriously outgunned and outnumbered by four-strokes.
R.I.P. THE JAPANESE TWO-STROKE
The modern four-stroke has definitely changed the dirtbike landscape. From the launch of the YZ400F, it only took around
