Triumph motorcycles require two things in order to run: Spark and fuel. Depending on the year and model of the bike, spark is generated by electrical current from a magneto or a 12-volt battery. Fuel systems consist of a petcock that controls the flow of fuel from the gas tank to a carburetor or fuel pump. Basic troubleshooting procedures can disclose most electrical or fuel problems in a matter of minutes. A shop manual for the year and model of the particular Triumph motorcycle contains wire codes and locations of certain components that require testing.
Things You'll Need
- Triumph workshop manual (year and model)
- Triumph tool kit
- Voltage meter
- Glass jar
Remove the battery cover using the appropriate tool from the Triumph tool kit. Connect the red and black voltage meter clips to the positive and negative battery posts. Red is always positive. Black is negative and ground.
Switch the voltage meter to 12 volts and check the reading. A fully charged battery will put out 12 to 14 volts. A reading of less than 12 volts indicates the battery must be charged. Batteries that have been inactive for long periods of time respond best to a slow, overnight charge. Remove the meter clips and charge the battery, if necessary, before proceeding.
Refer to the workshop manual and locate the ignition coil. Connect the red and black meter clips to the positive and negative terminals on the coil. Switch the voltage meter to 12 volts and note the reading. Typical ignition coil resistance is 0.5 to 1.5 ohms, or about one volt. A lack of resistance indicates the coil must be replaced.
Connect the red meter clip to the gray wire terminal on the back of the ignition switch. Connect the black clip to the head of a nearby bolt as ground. Turn the ignition switch to the "On" position and note the meter reading. A reading of less than 12 volts indicates a problem with the ignition switch.
Close the fuel petcock using the selector lever. Depending on the year and model of the motorcycle, the petcock is located at the underside, or at one side of the gas tank. Trace the path of the fuel line from the petcock to the carburetor or the fuel pump.
Remove the clamp where the fuel line connects to the carburetor or fuel pump using the appropriate tool. Position a glass jar under the connection. Pull the fuel line off and direct the end of the line into the jar.
Open the petcock and observe the flow of fuel into the jar. A lack of a consistent fuel-flow suggests a clogged petcock or clogged in-line fuel filter. A consistent flow of fuel indicates a problem with the carburetor. Proceed to the final steps to troubleshoot a fuel pump.
Close the fuel petcock. Reconnect the fuel line from the gas tank to the fuel pump and tighten the clamp. Remove the clamp that secures the fuel line at the output connection on opposite side of the pump. Hold the glass jar under the connection and pull the output line off the fuel pump.
Open the fuel petcock. Turn the ignition switch to the "On" position. A lack of fuel flow from the fuel pump output line indicates that the electrical fuse is bad, or the pump must be replaced.
Turn the ignition switch to the "Off" position and close the fuel petcock. Refer to the workshop manual for carburetor information, fuse replacement and fuel pump information.
Tips & Warnings
- Triumph gearboxes are notorious for grinding when first gear is engaged. Refer to the shop manual for clutch cable adjustment procedures.
- Troubleshoot fuel systems in a well-ventilated area.
- Photo Credit motorcycles taxi stand image by Diorgi from Fotolia.com
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