HMF YFZ450R Competition Series Exhaust and Fuel Optimizer Test

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See our fuel optimizer settings.    • HMF YFZ450R Competition Series Exhaus...  

To maximize the potential of our stock YFZ450R, we turned to the exhaust specialists at HMF. Their competition series exhaust is available as a slip-on silencer only, or with their stainless steel head pipe. Replacing the restrictive and heavier stock silencer yields the largest gains in power. Adding a head pipe often yields a bit more horsepower on stock engines, becoming even more important as you add a higher compression piston, cams, or other internal motor mods. As power hungry individuals, we opted to try the full Competition Series exhaust.

HMF’s Fuel Optimizer, manufactured by Dobeck, comes with a map pre-installed to work with HMF’s exhausts and the airbox lid removed. It features a decent range of on-board tune-ability, allowing you to dial in the amount of fuel injected on a scale of 1 to 8, at different RPM ranges.

A good aftermarket exhaust system and revised fuel map are essential for getting all the available power out of a modern, fuel-injected, sport ATV engine. We believe the performance of HMF’s Competition Series Exhaust and user-friendly, on-board adjustability of their Fuel Optimizer, really let us tap into the full potential Yamaha built into the YFZ450R’s engine. Its improved low-end performance and broad power band, with gains in performance throughout, substantially improve the race-ability of the YFZ450R for beginners and advanced racers alike.

The quiet core option and substantially enhanced low-end performance make this setup a great option for trail riders looking to improve performance with minimal effect on sound output. Of course, if you are like us and can benefit from more power one weekend and less sound the next, HMF seemingly designed the Competition Series Exhaust for you, and on the YfZ450R, it exceeded our expectations.