WHAT IS IT? Twin Air’s Yamaha YZ450F PowerFlow kit solves a design flaw in Yamaha’s air filter design.
WHAT’S IT COST? $259.95 (PowerFlow kit).
CONTACT? www.twinair.com or your local dealer.
WHAT STANDS OUT? Here’s a list of things that stand out with the Twin Air YZ450F PowerFlow air filter kit.
(1) The problem. Yamaha’s engineers dropped the ball on the original 2018 YZ450F air filter design and magnified the problem by not fixing it for 2019-2020 (changing it a little, but not solving any issues). The crux of the problem is that Yamaha’s flat, pancake-style air filter rests directly on the backfire screen of Yamaha’s downdraft intake system. Every time the engine pulses, which is typically 10,000 times a minute, the foam air filter is sucked against the wire screen. The constant vibration of the air filter sucks the air filter oil downward into the intake tract. The end result is that dirt can migrate through the now-dry foam. Additionally, the hole where the external cage’s pin goes through is not reinforced. Under the pulsing of the filter, the foam tears around the pin, creating a potential leak. On the 2020 model, Yamaha added a grommet to stop the pin from tearing the filter. On a final note, becaus eof the downdraft intalke and the upward slope of the airbox, dirt migrates to the bottom edge of the airbox and builds up at the bottom edge of the filter. It can be a lot of dirt on a. dusty day—and that dirt could get into the engine if the bottom edge of the filter is not held down tightly by the stock Yamaha cage.
Twin Air has two solutions for these issues.
(2) Solution #1: At the very least, a 2018–’2020 YZ450F owner should order Twin Air’s aftermarket air filter. Made from higher-quality and thicker foam, the Twin Air YZ450F filter also comes with a rubber grommet to reinforce where the cage pin goes through the filter. The finishing touch on the Twin Air YZ450F filter is a plastic spacer that plugs into the bottom of the new grommet and lifts the air filter 11mm above the YZ450F backfire screen. This stops the air filter from flapping against the wire screen
(3) Solution #2: The Twin Air YZ450F PowerFlow kit is the best all-around fix for the YZ450F airbox. With this kit, Twin Air replaces the stock sealing ring with an anodized aluminum mounting plate, gets rid of the backfire screen for uninterrupted airflow, adds a true-to-life internal filter cage (that supports a three-dimensional air filter), and finishes it off with a CNC-machined aluminum retaining knob to hold the filter in place. The design results in more air volume, increased air velocity, better sealing and peace of mind.
(4) Installation. It couldn’t be easier. All it takes is a Phillips-head screwdriver and 20 minutes to swap the Yamaha parts for the Twin Air parts.
WHAT’S THE SQUAWK? No complaints.
MXA RATING: If you don’t replace your stock YZ450F air filter with one of the two Twin Air options, you are risking your bike’s top end.