When Yamaha redesigned the YZ450F engine back in 2010, it really struck a balance between power and control. The 2015 version carried top-shelf racers such as Weston Peick and Justin Barcia to podium finishes, so there is no denying that the largest of the YZ family is already an accomplished model. Not content to rest on its laurels, the factory introduced a number of improvements for the 2016 model year that carried over into 2017. How does one improve upon success? Let’s take a look and find out.