* Inspect the spark plug for damage, wear, or incorrect gaps.
* Check for proper installation, ensuring the spark plug is clean and connected securely.
2. Ignition Coil Issue:
* Test the ignition coil to ensure it is generating enough voltage to create a spark.
* Check the coil's connections to the electrical system and look for any damage.
3. Magneto Issues:
* Since your Yamaha 125 has magneto-powered ignition, check the magneto for proper functionality.
* Examine the magneto's points, condenser, and coil for signs of damage or corrosion.
4. Wiring Problems:
* Inspect the wiring circuit related to the ignition system, including the kill switch and any associated relays.
* Look for disconnected wires or loose connections.
5. Faulty CDI Unit (Capacitor Discharge Ignition):
* If your 1974 Yamaha 125 uses CDI ignition, check the CDI unit for any damage or corrosion.
* Verify its connections to the electrical system are secure and not damaged.
6. Timing Issues:
* In case of magneto ignition, ensure the timing of the ignition system matches the specifications for your motorcycle.
* Verify the points' gap and ignition advance are correctly set.
