Kunray KR5V V2 72V 5000W New Upgrade Electric Brushless Motor Kit For Electric Motorcycle Razor Dirt Bike With 100A Fardriver Controller Bluetooth Built-in Half Handlebar LED Voltage Display Throttle #35 Chain Set

Machine Fitment

• Razor MX650, MX500, SX500, Indian650 and RSF650: the motor mounts directly into these chassis without modification, so a tired original unit can be swapped without fabricating brackets.
• Dirt bikes and mini e-motorcycles: as an electric dirt bike motor upgrade, it suits builds that want more pull out of the corners than a small stock unit can give.
• Go-karts and drift trikes: the mid-drive layout and chain drive to the rear axle match the frames most builders already run.
• Electric motorcycle conversions: replacing a brushless motorcycle motor of the same class usually means keeping your battery pack and rear wheel and changing only the motor and controller.

Fardriver Controller Setup

1. Mount the motor in the frame and line the sprocket up with the rear wheel so the chain runs straight.
2. Connect the phase and Hall cables. For left-side mounting with counterclockwise rotation, pair the phase wires yellow to yellow, blue to green, green to blue, and the Hall wires red to red, black to black, green to green, yellow to blue, blue to yellow.
3. Power up and let the controller's self-learning routine map the motor before the first ride.
4. Pair the controller with the Fardriver app over Bluetooth, on Android or iOS, and set power, speed and throttle response.
5. Change one setting at a time. Every 72V motor kit build reacts differently to rider weight, wheel size and gearing, so test between adjustments.
6. Switch on the reverse function in the app if your build needs it, then watch the temperature reading on the first few runs.

Riding Limits & Safety

Every 5000W motor kit build has limits, and this one is intended for off-road use. Check your local rules before riding anywhere public — roads and sidewalks may be off limits, and riding legally stays the rider's responsibility.

Published figures assume a healthy battery, correct gearing and firm ground. Real speed, acceleration and range shift with rider weight, wheel size, tire type, sprocket ratio and surface, so treat the numbers as a starting point for your own build rather than a promise.

Heat is the main thing to watch. Keep this brushless dc motor below 65 °C (150 °F); the KTY84-130 sensor reports live temperature so you can ease off before damage sets in. Sand, steep grades and heavy riders work the motor hardest, so gear the build around the terrain you actually ride.

Housing & Shaft Updates

• New motor case: the housing was updated in September 2025, and if the rear case cracks within six months of your order, the support team will replace it free of charge.
• Stronger sprocket interface: the shaft size changed and the sprocket diameter is larger, so the sprockets themselves carry more load.
• Reference codes: a reference is stamped into the case, which speeds up any after-sales check.
• Before you order: because the shaft and sprocket dimensions changed on this version, measure your current chain line and confirm your sprocket fit with the team first.

Technical Support & Model Matching

Not sure which motor suits your build? Our team helps you match a brushless motor or complete kit to your voltage, wattage, sprocket type and controller, so the parts work together from the first ride. We can advise on sine-wave controller pairings for Hall motors, sprocket and chain compatibility, and temperature-sensor options for builds that run hot. Need a base-mounted version or a different power rating? Just ask. We also guide installation, wiring and basic fault-finding once your order arrives.