Maintenance & Repair Changing the Lock Set on a D02 Ignition lock replacement, the wiring checks to do while you are in there, and the 0-gear confusion that follows. Applies to: D02 Classic, D02 Track How to change the lock set on the D02 — if the player does not load, open the video on YouTube. What you need Tool Notes Hex keys / socket set Panel and lock retaining hardware Replacement lock set See Spare Parts for the current price Camera Photograph the wiring before disconnecting Steps Power off and remove the key. Remove the panels covering the lock. Keep the fasteners together — they are small and easy to lose. Photograph the wiring at the back of the lock before you unplug anything. Disconnect the lock's connector, releasing the tab rather than pulling the wires. Remove the lock's retaining nut or clip and withdraw the lock from the frame. Fit the new lock, checking the barrel operates smoothly before you tighten anything down. Reconnect the wiring in the same orientation, then tug-test each connector. Refit the panels and test: power on, confirm the display lights. After refitting: the 0-gear check If the bike powers on but will not drive, check the gear display. It almost certainly reads 0. Press + to select gear 1 — this is not a fault. See Won't Turn On. Watch out for Swapping the connectors by guesswork. Photograph first — the color codes are not always obvious in low light. Over-tightening the retaining nut, which binds the barrel. Assuming a non-starting bike is a failed lock job. Check the gear display first. Related Won't Turn On Wiring & Connectors D02 Classic specifications Tutorials Index Installing the Front Disc Brake — Step-by-Step Caliper centering is the step that stops the brake dragging — and the one most often rushed. Applies to: D-series How to Install the Front Disc Brake on a CEMOTO Electric Dirt Bike | Step-by-Step Guide — if the player does not load, open the video on YouTube. What you need Tool Notes Hex keys Caliper and lever mounting bolts Torque wrench Caliper bolts are safety-critical — see Torque Reference Clean rag and isopropyl alcohol Never let brake fluid or oil touch the disc or pads ⚠ Never squeeze the brake lever with the caliper removed and the disc out. It pushes the pistons out and you will have to reset them. Steps Fit the disc to the wheel if it is not already mounted, and check it runs true. Mount the caliper with its bolts just snug — loose enough that the caliper can still slide side to side. Squeeze and hold the brake lever. This lets the caliper self-center on the disc. With the lever still held, tighten the caliper bolts to specification. This is the step that prevents a dragging brake. Release the lever and spin the wheel. The disc should run through the caliper with only a light, even contact — and no scraping in one spot. Fit the lever and set its reach and angle so it is comfortable and fully returns. Check the brake cut-off: with the bike powered, squeeze the lever and confirm the motor stops. If not, see E02. Bed the pads in with a few gentle stops from moderate speed before hard use. Watch out for Tightening the caliper before centering it — the single cause of a brake that drags. Getting oil on the disc or pads. Contamination is permanent — pads must be replaced, not cleaned. A lever that does not return fully. It holds the brake on and triggers E02. Check the pivot and clearance. Not testing the cut-off. The interlock is a safety feature, not a formality. Related Brakes — symptom diagnostics Brake Error E02 Torque Reference Tutorials Index Installing a CEMOTO Motor — Step-by-Step Wiring orientation, phase order, mounting and the first-run checks that confirm you got it right. Applies to: D-series How to Install a CEMOTO Motor | Step-by-Step Tutorial — if the player does not load, open the video on YouTube. What you need Tool Notes Socket set Axle nuts and mounting hardware Torque wrench See Torque Reference Insulating tape / heat shrink For any repaired cable run Cable ties Replace the ones you cut ⚠ Warranty note. Opening a motor voids the warranty on that part. Follow CEMOTO support's instructions for a warranty replacement. See Warranty Claims. Steps Support the bike so the wheel is clear of the ground. Route the motor cable before mounting. Fit the cable into its frame guides first — it is far harder once the wheel is in place. Seat the motor in the swingarm/dropouts, checking any spacers or torque washers go back in the same positions. Fit the axle nuts finger-tight, then torque to specification with the wheel aligned. Connect the three phase wires. They are color-matched — match them exactly. Wrong phase order causes rough running or no rotation at all. Connect the hall sensor plug. Small, multi-pin, easy to seat only halfway. Push until it clicks, and check no pin has backed out. Refit the chain / belt and set the tension — approximately 15 mm slack where a chain is used. Check the brake runs true and does not bind on the disc. Rotate the wheel by hand before applying power. It must turn freely with no rubbing. Power on and test at walking pace, then check for error codes. E07 here means the phase or hall connection needs rechecking — see E07. Watch out for Cross-threading an axle nut. Start them by hand, always. Getting phase order wrong. Match the colors; do not trust that they were right before. Leaving the hall sensor plug half-seated. It produces an intermittent E07 that is maddening to trace later. Reusing cut cable ties — replace them. Related Motor Removal Motor Error E07 Torque Reference Tutorials Index Removing a CEMOTO Motor — Step-by-Step Safe removal, and the inspection you should do while the motor is out. Applies to: D-series How to Remove a CEMOTO Motor | Step-by-Step Tutorial — if the player does not load, open the video on YouTube. What you need Tool Notes Socket set Axle nuts and mounting hardware Side cutters Cable ties — you will cut some Pen and phone camera Photograph every connector before you unplug it ⚠ Warranty note. Opening a motor voids the warranty on that part. Removal for a warranty replacement should follow CEMOTO support's instructions. See Warranty Claims. Steps Power the bike off and let it stand. Support the bike with the wheel clear of the ground. Photograph the wiring at the motor before touching anything — phase order and connector orientation are easy to forget. Release the chain / belt tension and move it clear of the sprocket. Disconnect the three phase wires and the hall sensor plug. Pull connector bodies, never the wires. Remove the axle nuts and note the position of any spacers or torque washers. Lower the wheel out of the frame. It is heavy — support it as it comes free. Inspect before you go further: phase wire chafing, hall plug pin condition, bearing play, and any sign of water ingress at the cable entry. While the motor is out Check Why Bearing play Spin the wheel and feel for roughness or lateral movement Cable entry Water ingress here causes intermittent faults for months Sprocket wear Far easier to replace now than after refitting Brake disc condition Check for warping or scoring while it is off the bike Related Motor Installation Motor Error E07 Torque Reference Tutorials Index