In 1998 Doug Henry piloted Yamaha’s innovative new four-stroke YZ400F to The AMA Motocross Nationals championship and in doing so, unwittingly signed the death warrant for all two-stroke motocross bikes in professional competition. Less than ten years later every motorcycle at the starting gate of an AMA sanctioned event was a thumper. The future had arrived and it was fast with gobs of torque. It was also loud – really loud. Bikes that ran closed-course-competition-only full exhaust systems routinely exceeded 105 decibels. Noise pollution issues started to plague tracks and compounded existing land access issues for recreational riders. The future of motocross had become fast, loud, and a bit bleak in terms of noise pollution conflicts.
Now the future has arrived again. It’s fast with gobs of torque, but this time it’s quiet – really quiet. Zero Motorcycles, the leading manufacturer of electric motorcycles, has unleashed the 2013 Zero MX. With eye-popping spec numbers like 68ft-lbs of torque and a top speed of 85 mph (70 mph sustained) the Zero MX is poised to make a statement at any motocross track.
There are a few subtle differences between a standard motocross bike and the Zero MX, like the fact that the Zero doesn’t have an engine. Instead it uses an air-cooled, high-efficiency, brushless motor connected to a 420 amp, brushless controller.
The motor is powered by a modular power pack system – using two batteries extends range and/or ride time and subsequently extends the life of the power pack(s). Dropping one of the battery packs obviously reduces ride time, but it also decreases weight by over 40 pounds; it’s like going from a plus sized model to a starving Ethiopian. This brings the Zero down to 223 pounds, which is comparable to a CRF250R with a full tank of gas.
The Zero MX comes equipped with 38mm front forks and a remote reservoir rear shock. Both front and rear suspension feature adjustable preload and rebound dampening. The suspension works in conjunction with a lightweight aircraft grade aluminum frame that is shot peened and anodized (which increases surface hardness and corrosion resistance), providing a chassis that is lightweight, strong, and responsive.
Nissin Brakes help to keep all that torque in check and prevent the rider launching himself off the track and into the parking lot.
For more timid riders, torque and top speed can be governed by an App for both iPhone or Android. This App also allows users to see detailed information such as charge time, total charge cycles, and more. When riding the phone app can be used to provide bike info in real-time.
While there are obvious differences between the Zero and standard dirt bikes, the variations between the MX and the only other dirt friendly bike within the Zero family are less blatant. (Assuming you disregard the Zero DS Dual Sport, which technically can go in the dirt but tips the scales at a bloated 395lbs – comparing the two would be akin to comparing a BMW R1200GS to a RMZ450.) In fact, the Zero FX Stealth Fighter is almost identical to the MX with the exception of having a street legal lighting kit (which adds 10 pounds) and carbon fiber belt and pulley direct drive instead of the MX’s 520 chain and sprocket. Speaking of the MX’s sprocket, with 65 teeth it’s the approximate diameter of a hula hoop.
Whether or not the Zero MX will have the same profound effect on motocross racing as the modern four-stroke is yet to be seen. With the AMA segregating classes by engine displacement and not offering an Open Class, it won’t be eligible to compete in racing on the professional level at motocross tracks. This isn’t to say that the Zero couldn’t give combustion engine bikes a run for their money. In fact, they already have. On June 30 a Zero FX set the fastest time in the production based motorcycle class at the Pike’s Peak International Hill Climb with a 12:00 flat run. That’s a pretty loud statement from a really quiet bike.