Super73 R, S and Z series: display on, but the motor won't run or cuts out

Your Super73 turns on, but the motor won't run on throttle or pedal assist, or it cuts out unexpectedly. Super73 has a support article for the R, S and Z series that says a motor cut-off sensor out of adjustment can stop the bike from operating (Super73 cut-off sensor article). Short answer: work through Super73's initial checks, then adjust the cut-off sensor at the brake lever in small steps, and make sure the motor still cuts out when you brake.

Most likely cause

On these bikes the cut-off is a pressure sensor at the brake. When it detects brake pressure, it cuts power to the motor (Super73 cut-off sensor article). If it is set too sensitive, it can read a brake that isn't being applied and keep the motor off. Super73 says loosening the sensor's adjustment screw is the more common fix, because it relieves pressure on the sensor (same article).

Other causes to rule out

Super73 asks owners to do these checks before contacting support (Super73 initial troubleshooting):

• Loose or damaged plugs under the seat and at the motor, including battery to controller, controller to the main harness, and the harness to the display, throttle and brakes.
• Pending firmware updates in the Super73 app.
• Whether the problem is on pedal assist, throttle or both.
• A part such as the throttle, display or battery, which you can swap with a known-good one to isolate the fault.
• A battery that isn't fully charged.

How to confirm

1. Charge the battery to 100% and try again (Super73 initial troubleshooting).
2. Note whether pedal assist, throttle or both fail.
3. With the battery off, reseat each connection under the seat and at the motor, and look for damage (same article). See inspect and clean connectors.
4. Connect in the Super73 app and install any updates (same article). See update e-bike firmware.
5. As a test only, Super73 suggests disconnecting the motor cut-off sensors at both brake levers to see whether anything changes (same article). If the motor now works, a sensor is the cause. Reconnect both before riding.
6. Find the sensor where the smaller cable enters the brake handle near the lever (Super73 cut-off sensor article).

Fix options

Reseat plugs and update firmware (easy)

Free, and the first thing Super73 support will ask about (Super73 initial troubleshooting).

Adjust the cut-off sensor (easy)

Super73 describes turning the sensor's adjustment screw with a 5mm wrench in small steps. Counterclockwise makes it less sensitive, so it cuts later in the lever pull. Clockwise makes it more sensitive (Super73 cut-off sensor article). After each small change, check on a stand that the motor stops as soon as you pull the lever, then take a short, careful test ride. Our guide to checking the brake cut-off and throttle helps.

Replace a sensor or controller (Super73 support)

If adjusting doesn't help, open a ticket with a video and the steps you tried, a screenshot of firmware versions from the app, your receipt and serial numbers (Super73 initial troubleshooting). Super73 publishes controller replacement guides for its models, such as the Z series guide for the ZX, Z Miami and Z Adventure (Z series controller guide), but let support confirm the diagnosis first.

Parts

• Brake cutoff sensor
• E-bike controller

Videos

When to get a pro

Get help if the motor keeps running when you brake, if brakes feel weak, or if adjustment and plug checks don't restore power. Super73's support hub lists service centers. See also motor cuts out and Super73 troubleshooting.

Sources

• Super73 cut-off sensor article, support.super73.com
• Super73 initial troubleshooting, support.super73.com
• Z series controller guide, support.super73.com
• support hub, super73.com
• Adjusting a Motor Shutoff Brake Sensor, youtube.com

Stuck after these checks? Find a shop near you.