MXA TECH SPEC: IS BNG A DEAL-BREAKER?

The 2021 Yamaha YZ450F is unchanged from the previous year save for BNG.

When a motocrosser sees that a new bike, like the 2021 YZ450F, Suzuki RM-Z450 or Honda CRF250, has only received BNG (bold new graphics), he crosses it off his must-have list. BNG is the kiss of death. When buyers are constantly bombarded with “new,” “radical,” “ground-breaking” and “revolutionary,” they don’t find new graphics to be noteworthy. But, let’s take a close look at the 2021 Yamaha YZ450F and see if that kiss is actually fatal. During the four-year production cycle of the 2021 Yamaha YZ450F, it hasn’t sat still, even if the non-initiated think that the 2021 YZ450F is just a warmed-over 2018 model. Need proof? Here are the list of changes that Yamaha’s engineers have made since the 2018 model was introduced. 

2018. With the addition of electric starting and Wi-Fi mapping, the 2018 YZ450F got new camshaft profiles, a redesigned crankshaft, a higher-compression piston and a 44mm Mikuni EFI throttle body (instead of Keihin). The cylinder was slanted 2 degrees more upright. The radiators were enlarged, the muffler was moved farther forward and the radiator shrouds were redesigned. The seat was 9mm lower at the front and 18mm lower at the rear. The bar mounts were raised 5mm, and the now-aluminum head stays were repositioned lower on the cylinder. Oh yeah, the rims were blue anodized.

2019. For 2019, the YZ450F received updated Kayaba SSS suspension valving, more rigid fork lugs, stiffer wheel collars, less drag on the electric starter system, 16-percent-denser seat foam and a blue valve cover. The transmission and clutch were overhauled for a more direct connection, as well as enhanced durability. Revised gears with a wider surface area, updated clutch plates and a stiffer clutch pressure plate enhanced the driveline.

2020. The cylinder head was 10mm narrower. The breather hose outlet moved to the valve cover. The head pipe was attached with two studs instead of three. The camshafts were moved 14mm closer together. The cam towers were 6mm lower. The valve stems were 6mm shorter. The valve angle was 7 degrees more upright. The combustion chamber volume was reduced 6.65cc. The compression was raised from 12.9:1 to 13.0:1. The spark plug extends 4.9mm into the burn area. The top ring’s tension was increased by 10 percent. The connecting rod was made 1.5mm longer to reduce friction by 2 percent. A new ECU map improved low-rpm throttle response. The exhaust pipe was 3.2mm larger at the first turn of the mid-pipe (38.1mm to 41.3mm diameter). The regulator and rectifier were bundled into one unit.

2021. BNG. So, why didn’t Yamaha do anything to improve the 2021 YZ450F? There are three reasons: (1) The four-year production plan only guarantees a return on investment if there are no changes to the 2018 YZ450F through the 2021 model years. Of course, there will always be small updates to fix flaws that surface during the first year of production, but the list of Yamaha’s mechanical changes over since 2018 far exceeds what the pencil pushers in accounting expected. (2) Since the 2018 YZ450F was introduced, Yamaha has made a lot of expensive changes. (3) Assuming that Yamaha is sticking to the traditional four-year plan, there might be an all-new YZ450F in 2022. If that is true, it would be wasted money for Yamaha to make more changes to the original 2018 machine in its fourth year, given that something new could be on the horizon.

Over the last four years Yamaha didn’t sit on its original 2018 design, which is what the Japanese motorcycle manufacturer’s playbook calls for. Instead, the engineers made constant improvements to the YZ450F’s performance. While you might look at the BNG changes to the 2021 YZ450F as a deal-breaker, you will be ignoring the three years of work that went into making the 2021 YZ450F as good a bike as it is.