Diagnosing the problem when your bike won’t start can be difficult. Check out this guide for common reasons for the RS125 not starting. Work your way through the checklist from top to bottom.

RS125 Non-Starter Checklist

• If there is a nick in a tube or you have a leaky carburettor, your fuel could have escaped and evaporated over the course of a few hours (Lift your filler cap and check that there is fuel visible in your tank).
• Someone could have played with it since you last rode the bike or you might have forgotten.
• Put the bike in neutral and push along with your feet (or have someone push you).
• When you have reached a good speed, put the bike into SECOND gear and hit the starter button.
• If she starts up, pull the clutch in. The problem would appear to be in the starter motor.
• The starter relay can be found behind the radiator and the connection means that it is possible for wires to fall out of the unit.
• If you can bump start the bike and the wires are all connected, the problem could lie within the relay.
• Turn the engine over and make sure that a good volume of air is coming out of the exhaust.
• If possible, take it off the bike and look for blockages.
• Make sure the choke is not flooding the engine.
• Remove the seat and lift the tank up.
• Either remove the spark plug or take a good plug that you are certain work, and connect it to the HT cap.
• Touch the end of the plug to the frame via the insulated cap as you are in for a shock (haha) if you hold the plug itself.
• Hit the starter button and look for a spark.
• Check the original plug in the same way to make sure that it isn’t the source of the problem.
• Make sure that the HT lead sits snuggle onto the plug.
• Make sure that everything is plugged into the CDI as it should be.
• This is located underneath the pillion seat. Look for bare or cut wires.