# 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

---

<div align="center">

<iframe width="720" height="405"
        src="https://www.youtube.com/embed/qi07ww3o8rU?rel=0"
        title="How to change the lock set on the D02"
        frameborder="0"
        allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
        referrerpolicy="strict-origin-when-cross-origin"
        allowfullscreen></iframe>

<sub>*How to change the lock set on the D02* — if the player does not load, [open the video on YouTube](https://www.youtube.com/watch?v=qi07ww3o8rU).</sub>

</div>

---

## What you need

| Tool | Notes |
| --- | --- |
| Hex keys / socket set | Panel and lock retaining hardware |
| Replacement lock set | See [Spare Parts](https://wiki.cemotoride.com/link/382) for the current price |
| Camera | Photograph the wiring before disconnecting |

---

## Steps

1. **Power off** and remove the key.
2. **Remove the panels** covering the lock. Keep the fasteners together — they are small and easy to lose.
3. **Photograph the wiring** at the back of the lock before you unplug anything.
4. **Disconnect the lock's connector**, releasing the tab rather than pulling the wires.
5. **Remove the lock's retaining nut or clip** and withdraw the lock from the frame.
6. **Fit the new lock**, checking the barrel operates smoothly before you tighten anything down.
7. **Reconnect the wiring** in the same orientation, then tug-test each connector.
8. **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](https://wiki.cemotoride.com/link/365).

---

## 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](https://wiki.cemotoride.com/link/365)
- [Wiring & Connectors](https://wiki.cemotoride.com/link/355)
- [D02 Classic specifications](https://wiki.cemotoride.com/link/314)
- [Tutorials Index](https://wiki.cemotoride.com/link/393)

# 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

---

<div align="center">

<iframe width="720" height="405"
        src="https://www.youtube.com/embed/K8ZhlgfK0hE?rel=0"
        title="How to Install the Front Disc Brake on a CEMOTO Electric Dirt Bike | Step-by-Step Guide"
        frameborder="0"
        allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
        referrerpolicy="strict-origin-when-cross-origin"
        allowfullscreen></iframe>

<sub>*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](https://www.youtube.com/watch?v=K8ZhlgfK0hE).</sub>

</div>

---

## What you need

| Tool | Notes |
| --- | --- |
| Hex keys | Caliper and lever mounting bolts |
| Torque wrench | Caliper bolts are safety-critical — see [Torque Reference](https://wiki.cemotoride.com/link/325) |
| 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

1. **Fit the disc to the wheel** if it is not already mounted, and check it runs true.
2. **Mount the caliper** with its bolts **just snug** — loose enough that the caliper can still slide side to side.
3. **Squeeze and hold the brake lever.** This lets the caliper self-center on the disc.
4. **With the lever still held, tighten the caliper bolts** to specification. This is the step that prevents a dragging brake.
5. **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.
6. **Fit the lever** and set its reach and angle so it is comfortable and fully returns.
7. **Check the brake cut-off:** with the bike powered, squeeze the lever and confirm the motor stops. If not, see [E02](https://wiki.cemotoride.com/link/358).
8. **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](https://wiki.cemotoride.com/link/328)
- [Brake Error E02](https://wiki.cemotoride.com/link/358)
- [Torque Reference](https://wiki.cemotoride.com/link/325)
- [Tutorials Index](https://wiki.cemotoride.com/link/393)

# 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

---

<div align="center">

<iframe width="720" height="405"
        src="https://www.youtube.com/embed/BEzjheNY9H4?rel=0"
        title="How to Install a CEMOTO Motor | Step-by-Step Tutorial"
        frameborder="0"
        allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
        referrerpolicy="strict-origin-when-cross-origin"
        allowfullscreen></iframe>

<sub>*How to Install a CEMOTO Motor | Step-by-Step Tutorial* — if the player does not load, [open the video on YouTube](https://www.youtube.com/watch?v=BEzjheNY9H4).</sub>

</div>

---

## What you need

| Tool | Notes |
| --- | --- |
| Socket set | Axle nuts and mounting hardware |
| Torque wrench | See [Torque Reference](https://wiki.cemotoride.com/link/325) |
| 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](https://wiki.cemotoride.com/link/389).

---

## Steps

1. **Support the bike** so the wheel is clear of the ground.
2. **Route the motor cable before mounting.** Fit the cable into its frame guides first — it is far harder once the wheel is in place.
3. **Seat the motor in the swingarm/dropouts**, checking any spacers or torque washers go back in the same positions.
4. **Fit the axle nuts finger-tight**, then torque to specification with the wheel aligned.
5. **Connect the three phase wires.** They are color-matched — **match them exactly**. Wrong phase order causes rough running or no rotation at all.
6. **Connect the hall sensor plug.** Small, multi-pin, easy to seat only halfway. Push until it clicks, and check no pin has backed out.
7. **Refit the chain / belt** and set the tension — approximately 15 mm slack where a chain is used.
8. **Check the brake** runs true and does not bind on the disc.
9. **Rotate the wheel by hand** before applying power. It must turn freely with no rubbing.
10. **Power on and test at walking pace**, then check for error codes. E07 here means the phase or hall connection needs rechecking — see [E07](https://wiki.cemotoride.com/link/360).

---

## 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](https://wiki.cemotoride.com/link/353)
- [Motor Error E07](https://wiki.cemotoride.com/link/360)
- [Torque Reference](https://wiki.cemotoride.com/link/325)
- [Tutorials Index](https://wiki.cemotoride.com/link/393)

# Removing a CEMOTO Motor — Step-by-Step

> Safe removal, and the inspection you should do while the motor is out.
>
> **Applies to:** D-series

---

<div align="center">

<iframe width="720" height="405"
        src="https://www.youtube.com/embed/yjHDsPmQ-OI?rel=0"
        title="How to Remove a CEMOTO Motor | Step-by-Step Tutorial"
        frameborder="0"
        allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
        referrerpolicy="strict-origin-when-cross-origin"
        allowfullscreen></iframe>

<sub>*How to Remove a CEMOTO Motor | Step-by-Step Tutorial* — if the player does not load, [open the video on YouTube](https://www.youtube.com/watch?v=yjHDsPmQ-OI).</sub>

</div>

---

## 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](https://wiki.cemotoride.com/link/389).

---

## Steps

1. **Power the bike off** and let it stand.
2. **Support the bike** with the wheel clear of the ground.
3. **Photograph the wiring** at the motor before touching anything — phase order and connector orientation are easy to forget.
4. **Release the chain / belt tension** and move it clear of the sprocket.
5. **Disconnect the three phase wires** and the hall sensor plug. Pull connector bodies, never the wires.
6. **Remove the axle nuts** and note the position of any spacers or torque washers.
7. **Lower the wheel out** of the frame. It is heavy — support it as it comes free.
8. **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](https://wiki.cemotoride.com/link/352)
- [Motor Error E07](https://wiki.cemotoride.com/link/360)
- [Torque Reference](https://wiki.cemotoride.com/link/325)
- [Tutorials Index](https://wiki.cemotoride.com/link/393)