There can be several reasons why your Yamaha YZF-R 125cc petrol bike won't start. Here are a few common issues to check:
Fuel Issues: Ensure that your bike has enough fuel in the tank. Check if the fuel valve is open and that the fuel line is not clogged. If the fuel is old or contaminated, it may need to be drained and replaced.
Battery: Check the battery voltage using a multimeter. If the battery is low or completely discharged, it may not have enough power to start the bike. Try jump-starting the bike or charging the battery.
Spark Plug: A faulty spark plug can prevent ignition. Remove the spark plug and inspect it for signs of damage or wear. Clean or replace the spark plug if necessary.
Ignition System: Check the ignition switch, kill switch, and ignition coil for any faults. Ensure that the wires are properly connected and that there are no loose connections or damaged components.
Air Filter: A clogged or dirty air filter can restrict airflow to the engine, affecting starting and performance. Clean or replace the air filter if it is dirty.
Carburetor: If the bike has been sitting idle for a while, the carburetor may be clogged with old fuel or debris. Cleaning the carburetor or having it professionally serviced may be necessary.
Electrical Issues: Check the wiring harness for any damaged or loose connections. Inspect the fuses to ensure they are intact.
If you have checked these common issues and are still unable to start your bike, it is recommended to consult a qualified mechanic or Yamaha service center for further diagnosis and assistance. They will have the expertise and tools necessary to identify and resolve the problem.