Retrospective: 20 Years of Yamaha YZ Four-Stroke MXers

Yamaha introduced the YZ400F four-stroke motocross machine 20 years ago. Here’s a look back at the generations of YZs that lead to the 2018 YZ450.

Has it really been 20 years since Yamaha shifted the paradigm of motocross development from two-stroke back to four-stroke power with the introduction of the YZ400F? Indeed it has, and yet the pace of motocross bike development as slowed so little that even the revolutionary YZ400F seems by today’s standards, which are pretty much empbodied in the recently announced 2018 Yamaha YZ450F.

So, just for giggle, we thought it would be fun to go back and take a look at the previous generations of YZ four-strokes, highlighting the key changes that each brought to the party.

1997 Yamaha OWH2

This was the spark that ignited the modern four-stroke motocross revolution. With factory Yamaha rider Doug Henry aboard, the OWH2 proved the concept. Using an rule that allowed prototype motorcycles to race against production machines in AMA Natonal competition, Henry shocked fellow racers and fans alike by winning the 1997 Las Vegas Supercross.