We have recently received feedback from some customers regarding the performance of the HM-01 CDI system. To ensure transparency and help you resolve any issues quickly, we would like to provide a clear explanation along with our current solutions.

🔧 HM-01 Starting Issue Troubleshooting Guide

If you are experiencing issues where the engine cannot start or is difficult to start, please check the following points step by step:

1️⃣ Valve Clearance (Very Important)

Please check whether you have correctly adjusted the valve clearance according to the manual.

⚠️ If the valve clearance is not set properly, the valve may remain in a compressed/open state, resulting in no cylinder compression, which will prevent the engine from starting.

2️⃣ Mechanical Ignition U-shaped Spring

Please check the U-shaped spring of the mechanical ignition system.

⚠️ If it has been bent too much, it may lose elasticity and fail to properly trigger the electrode contact, causing ignition failure.

3️⃣ Carburetor Main Needle Setting

Please verify your carburetor main needle setting.

• Recommended setting: 1/5 – 1/4 turn open
• If it is opened too much (e.g., around 1.5 turns), the fuel-air mixture will be too rich, making the engine difficult to start.

4️⃣ Final Adjustment Result (Reference)

After correctly adjusting the above points:

• Valve clearance properly set
• U-shaped spring restored with proper elasticity
• Ignition timing adjusted (approximately 5° advance)
• Carburetor reset to correct needle position

👉 The engine should start easily and run smoothly.

1. Upgrade Overview of the New CDI

The latest version of the HM01 CDI has been upgraded with the following improvements:

• ✅ Integrated ignition LED indicator, allowing users to easily monitor the working status
• ✅ Significantly reduced size, making installation more convenient, especially inside compact wooden equipment boxes

However, due to the upgraded design, the new CDI has higher voltage requirements.

👉 It must be powered by:

• 11.1V (3S LiPo battery ×1)
• or 7.2V (18650 battery ×2 in series)

⚠️ Based on current feedback, most abnormal behavior is caused by insufficient battery voltage, rather than a defect in the CDI itself.

2. Ongoing Factory Inspection

We have already arranged for several returned units to be sent back to the factory for further inspection.

• 🔍 Testing is still in progress
• We are closely monitoring the results to ensure full accuracy and transparency

3. Current Inventory Testing Results

The factory has completed testing on the existing CDI inventory.

✔️ All tested units are functioning properly
✔️ No quality issues have been identified

4. Root Cause Analysis & Next Steps

If a CDI issue persists—even after a replacement unit has been provided—the root cause can almost certainly be identified as:

👉 Battery-related issues (insufficient voltage or unstable output)

To improve user experience and avoid similar issues in the future:

• We are planning to select and offer high-quality, verified batteries
• These batteries will be made available as recommended or bundled products

5. Temporary Solution for Affected Customers

For customers whose issues have not yet been resolved, we are currently offering a temporary solution:

🔁 Replacement with the previous-generation CDI

This solution has proven to be more tolerant of different power conditions and can help restore normal operation while we continue optimizing the new version.

Final Notes

We sincerely appreciate your patience and feedback. Your input plays a crucial role in helping us improve our products and deliver a better experience.

If you are experiencing any issues, please feel free to contact our support team—we are here to help.