Could This Yamaha XE4 Electric Dirt Bike Take Over The Motocross World?

If you've ever attended a Motocross race and heard the throaty growl of powerful four-stroke dirt bikes as the riders navigate the twists, turns, and jumps, it's hard to fathom a world where that sweet sound could be replaced by the whine of electric power. However, the sport of motocross changes more than many people may realize, it just does so gradually.

The decision of whether or not an electric dirt bike could take over the motocross world won't necessarily come down to which is better on the track or more popular with the fans. Take the transition from 2-stroke dirt bikes to the 4-stroke machines we see on the track today, for example.

The first 4-stroke to ever win a supercross race in the premier 250cc division was a YZ400F, marking the beginning of the end for the 2-stroke in motocross. How was a 400cc class machine allowed to compete with 250cc class dirt bikes? The American Motorcycle Association (AMA) — the sanctioning body for professional motocross and supercross racing in the United States — changed the rules to allow larger displacement 4-strokes to compete with 2-strokes.

Yamaha points to "the push for more environmentally friendly machines" as the impetus for 4-stroke dirt bikes — which sounds like a familiar argument for electric vehicles vs. gas engines in general.

Will electric dirt bikes take over motocross? Only time will tell, but the XE4 — a converted Yamaha YZ250F — could be a step in that direction, once the bugs are worked out.

Tucker Neary, of Electric Cycle Rider, reviewed an XE4 in early 2023. Neary described riding the electric motocross bike like "riding a Yamaha YZF250F, albeit with an electric powertrain, which is a great thing."

There are two XEMX conversion kit versions for YZ250F and YZ450F dirt bikes, the air-cooled XE2 and liquid-cooled XE4, however only the XE4 pre-order option is available on the XEMX website. The XE4 replaces the gas engine in the 2014 to 2019 YZ250F and 2014 to 2018 YZ450F model chassis. Using the stock YZF radiator, the kit includes a 12-volt pump to circulate coolant to keep the electric motor cool. The test bike used a 2016 YZ250F chassis and the XE4 conversion kit.

The XE4 features 72-volt battery power delivering up to 600 amps and 4.3 kWh. The "axial flux motor" uses a "carbon fiber sleeved rotor" and ceramic bearing to deliver a maximum 58 horsepower rating. XEMX lists its Complete Motor A Kit at $6,995 and the Quick Swap Batteries for $3,295 each. For comparison, OEM Dirt Bike Parts lists a 2024 YZ250F crate engine for sale priced at $6,999.90.

In addition to the electric conversion kits, XEMX is taking preorders for XE4 Complete Custom Bikes. Original pricing of $16,500 is currently reduced to $12,950 and the bikes come in Blue or Gray as shown above. 

As electric dirt bikes evolve, they keep getting better. The XE4 has demonstrated its competitiveness at events like the 2022 Red Bull Tennessee Knock Out eMoto race with Joseph Toole aboard for a second-place finish, completing the course in just under 55 minutes. B.W. Haskell rode a 2018 Alta Redshift MXR to win SoCal OTMX club's "Support" class at Cahuilla Creek MX.

As far as power output, the XE4's 58-horsepower maximum rating compares favorably with the 2023 Yamaha YZ450F, which is rated at 59 horsepower. Professional motocross and Nascar competitor, Travis Pastrana thinks the 80-hp Stark Varg has potential as a freestyle motocross bike and was able to ride a full moto using a fourth of the bike's battery capacity. Pastrana feels electric dirt bikes, with their quiet motors, could save local motocross tracks from being shut down over noise complaints from nearby neighbors.

Will the XEMX Yamaha XE4 electric dirt bike take over the motocross world? Probably not in its current form. However, electric dirt bikes are coming, and as they get better, track promoters, race sanctioning bodies, and riders will come to enjoy their benefits. Much like four-strokes replaced the old two-stroke, electric dirt bikes will phase out gas-powered bikes eventually.