Electric Motocross Bikes are rapidly changing the off-road riding landscape. While groundbreaking models like the Stark VARG and Flux Primo are capturing headlines, the earlier departure of Alta Motors still leaves enthusiasts wondering when major manufacturers like Honda, Yamaha, and KTM will fully commit to the electric dirt bike market.
In the midst of this anticipation for cutting-edge electric motorcycles, it’s easy to forget the decades of engineering and refinement invested in existing motocross bike chassis. These finely-tuned machines, developed by top engineers and racers, are perfect candidates for electric conversions. Fortunately, companies are emerging to bridge this gap, offering electric conversion kits designed for proven motocross platforms.
One such innovator is Xtreme Electric MX (XEMX), with their Yamaha XE4 Electric Dirt Bike conversion kit. After seeing several successful electric conversions, the XE4 Yamaha from XEMX has particularly caught our attention. Our interest intensified after witnessing JoJo Toole’s impressive performance on this bike at the 2022 ECR eMoto Race during the Red Bull TKO event.
Jojo Toole skillfully racing an electric motocross bike, the Yamaha XE4, at the 2022 Red Bull TKO eMoto competition.
Decoding the XEMX Yamaha Electric Dirt Bike: Specs and Features
XEMX offers two distinct conversion kits: the XE2 (air-cooled) and the XE4 (liquid-cooled). The XE4, a bolt-on kit, is engineered for compatibility with Yamaha 250 and 450 YZF and YZFX models. It fits 250 chassis from 2014-2019 and 450 chassis from 2014-2018.
Close-up view of the XEMX XE4 electric motocross conversion kit expertly installed on a Yamaha YZF chassis, showcasing the integration of electric components.
The liquid-cooled XE4 system cleverly utilizes the stock Yamaha YZF radiators, incorporating a small 12V pump to circulate coolant, ensuring optimal motor temperature with Engine Ice. Liquid cooling is paramount for maintaining motor efficiency, as cooler operation translates to better performance. A standout feature of the XE4 is XEMX’s proprietary fast-change battery swap technology. This system boasts the quickest battery replacement on the market, enabling battery swaps in under 10 seconds.
The specific XE4 test bike we evaluated was built upon a 2016 Yamaha YZ250F chassis. Currently, XEMX employs a 12T front and 52T rear sprocket setup, with occasional adjustments to a 12T-54T combination. Notably, components like sprockets, plastics, suspension, and grips remain stock Yamaha parts, with front sprockets being sourced from a stock YZF450.
XEMX is actively testing various controllers to pinpoint the optimal one for overall performance. Controllers under evaluation include the Curtis 1236SE, Votol EM-260S, EBMX X-9000, Fardriver, Kelly, and the A5, a Curtis alternative. Each controller will undergo rigorous racing tests to determine the best fit for the electric motocross bike conversion.
During our test, the bike was equipped with the Curtis 1236SE controller, rated at 450 amps at 72 volts.
Side view of the Yamaha XE4 electric motocross bike highlighting the electric motor and components integrated within the Yamaha YZF frame.
XEMX batteries are rated at 72V nominal with a 600 Amp max output, providing a total capacity of 4.3kWh. Being custom-built, these batteries offer flexibility, allowing XEMX to tailor the cell type and quantity to meet specific customer requirements.
The proprietary fast-change battery swap system utilizes a modified aerospace connector, capable of handling 600 amps per terminal. The battery compartment is ingeniously designed, repurposing the original Yamaha YZF gas cap lid for a clean and efficient access point. This innovative design facilitates battery swaps in less than 10 seconds.
Close-up showcasing the quick-swap battery system on the Yamaha XE4 electric motocross bike, emphasizing the speed and ease of battery changes.
The XE4 offers three fully programmable ride modes, along with reverse functionality, auto regen braking, and optional lever regen braking. Adding a unique touch, the bike includes optional motor sounds via a speaker system, a feature rarely seen on electric motocross bikes.
Front three-quarter view of the Yamaha XE4 electric motocross bike, showcasing its overall design and stance as an electric conversion.
Currently, the XEMX Yamaha XE4 is available as a custom order, with kits slated for general sale after beta testing concludes. Cost breakdowns for the kits are detailed below.
Riding the Electric Yamaha XE4 Dirt Bike: Performance Impressions
While we’ve experienced the Stark VARG and Alta Redshift, our team frequently rides the KTM Freeride EXC and smaller electric dirt bikes like the Sur-Ron Light Bee X.
The XEMX Yamaha XE4 delivers a remarkable riding experience. The Yamaha YZF chassis has established itself as a dependable platform, largely attributed to its distinctive reverse motor design, generating horsepower that rivals competitors in the pro MX scene.
With the electric powertrain replacing the conventional gas motor, the original engine configuration becomes less relevant. However, the YZF design provides XEMX with adaptable space for motor and battery integration.
The Yamaha chassis is celebrated for its stability and planted feel in challenging terrains. The highly-regarded KYB SSS suspension comes standard on Yamaha YZF bikes and is a favorite among riders.
Riding the XEMX Yamaha XE4 validates the Yamaha YZF chassis’s reputation for stability and superior suspension. The bike feels exceptionally planted, particularly when compared to lighter electric dirt bikes under 150 pounds that struggle in Florida’s rough sand whoop sections. The sensation is akin to riding a Yamaha YZF250F, but with a seamless electric powertrain – a significant advantage.
If there’s any known characteristic of the YZF chassis, it’s a slight trade-off of front-end steering agility for enhanced stability. It’s often favored by riders who “steer with the rear” or prioritize stability over razor-sharp turning, unlike bikes from KTM, Suzuki, or Honda. However, these are minor nuances, and adjustments can be made to fine-tune the turning and front-end feel of the YZF chassis.
During our video review of the Yamaha XE4 electric dirt bike, we encountered a minor issue. The bike occasionally faulted when hitting sand whoops aggressively with hard throttle input. Mark from XEMX clarified that a slight misalignment between the sensor and magnet in the motor was causing intermittent shutdowns. This is a known, occasional issue with new motors, and XEMX has reportedly resolved 99% of these instances since filming, attributing the remaining issue to older connector types. Importantly, this issue is slated for complete resolution before kits become commercially available.
During field testing, Mark from XEMX adjusted the power output, reducing it by approximately 20%. Consequently, we tested the bike at only 80% of its potential power. The controller used in our test was rated for 450 Amps, while the batteries are capable of delivering up to 600 Amps. This indicates substantial untapped power potential within this platform.
XEMX Yamaha XE4 Electric Dirt Bike: Pricing and Kit Details
XEMX has not yet officially launched kit sales but is currently taking custom billet motor orders and providing necessary components for early adopters. With their complete A kit and a prepped rolling frame, assembly can be completed in a single day.
To undertake this conversion, you’ll need a Yamaha 250 YZF or FX (2014-2019) or a 450 YZF (2014-2018) rolling frame.
These motors feature full ceramic bearings and a carbon-sleeved rotor, finished in black (Cerakoting or powder coating available at extra cost).
BILLET 6061 ALUMINUM MOTOR ALONE: $3,500.
XE4 ALL BILLET AXIAL FLUX MOTOR WITH CARBON FIBER SLEEVED ROTOR, LIQUID COOLED, CERAMIC BEARING, 2.08 TO 1 GEAR REDUCTION. MAX RATING OF 58 HP @ 600 AMPS, NOMINAL 38 HP.
COMPLETE MOTOR A KIT: $6,995.
XE4 BILLET MOTOR AND KIT, INCLUDING:
- FULLY BUILT BATTERY TRAY, BATTERY SIDE BRACKETS, BUS BARS, AND PHASE WIRES.
- BRACKETS (FRONT, MID, AND TWO REAR SEAT BRACKETS), CARBON FIBER AIR BOX COVER, SEVEN PIVOT POINT HINGE, HALL THROTTLE, WATER PUMP, MAIN CONTACTOR, DC TO DC CONVERTER, 12T FRONT SPROCKET, CARBON FIBER AND MID SEAT PAD.
- CURTIS 1236SE-6571 PRE-PROGRAMMED CONTROLLER AND COMPLETE WIRING HARNESS, POWER PANEL, MODE AND ON/OFF SWITCHES.
QUICK SWAP BATTERIES SOLD SEPARATELY FROM THE KIT: $3,295.
INR 25R SAMSUNG (400) 18650 CELL BATTERY, 500 AMP PEAK AT 84V, 4KW, 10 MODULES (40 18650 CELLS EACH). MOLICEL P42 and P45 options are also now available.
OPTIONAL CHARGER: $250.
MODEL S2500 BATTERY CHARGER, INPUT: 120V AC VOLT, OUTPUT: 84V=10AMP WITH LED DISPLAY AND FINISH CHARGE INDICATOR. (Higher amp/faster charging options will be available).
OPTIONAL PROGRAMMER: $695.
HANDHELD PROGRAMMER FOR THE CURTIS SE1236-6571 CONTROLLER.
OPTIONAL SEAT: $250.
CUSTOM SEAT CONCEPTS SEAT COVER FOR QUICK SWAP BATTERY SYSTEM.
In conclusion, the Yamaha XE4 Electric Dirt Bike represents a compelling fusion of proven motocross chassis and innovative electric technology, offering riders eager for a full-size electric motocross bike a serious option to consider. With its potent electric powertrain and rapid battery swap system, the XE4 is a testament to ingenuity. While still undergoing final beta testing, XEMX is dedicated to making these conversion kits commercially accessible. For further details, contact Mark Peroni at www.xemx1.com or via email at [email protected].
