Yamaha’s engineers have taken the high-performance engine from the latest YZ450F and developed an all-new powerplant for this new WR450F, that is significantly lighter and more compact and achieves even stronger and controllable power across the rev range.
The new engine is essentially the new generation YZ450F tuned with enduro settings - which means its significantly more compact and lighter than the 2020 engine. Its new cylinder head weighs 310g less than before and is significantly more compact. And featuring increased compression ratio – up from 12.8:1 to 13:1 – the reverse cylinder head also runs a durable forged piston and aggressive cam profiles.
The intake/exhaust valve angles and intake port design are changed and a new piston with a small recess is specified to create a more concave combustion chamber for increased power. This new high-efficiency head with its long and straight inlet, produces a fine balance of power with exceptional controllability.
The combination of lower weight and reduced dimensions helps to achieve
enhanced mass centralisation, and this contributes enormously towards a lighter
feeling and increased agility when cornering – making the 2021 WR450F one of
the easiest-handling large-capacity enduro models.