TROUBLESHOOTING
1
39
OPERATING REQUIREMENTS An engine needs three basics to run properly: correct fuel/air mixture, compression and a spark at the right time. If one basic requirement is missing, the engine will not run. Four-stroke engine operating principles are described in Chapter Four under Engine Principles.
2
If the motorcycle has been sitting for any time and refuses to start, check and clean the spark plugs. If the plugs are not fouled, look to the fuel delivery system. This includes the fuel tank, fuel shutoff valve, fuel filter and fuel lines. If the motorcycle sat for a while with fuel in the carburetor, fuel deposits may have gummed up carburetor jets and air passages. Gasoline tends to lose its potency after standing for long periods. Condensation may contaminate it with water. Drain the old gas and try starting with a fresh tankful.
STARTING THE ENGINE Engine Fails to Start (Spark Test) ample, note whether the engine lost power gradually or all at once, what color smoke came from the exhaust, etc. After defining the symptoms, follow the procedure that most closely relates to the condition(s). Guessing at the cause of the problem may provide a solution, but it can easily lead to wasted time and unnecessary parts replacement. Expensive equipment or complicated test gear is not required to determine whether repairs can be attempted at home. A few simple checks could save a large repair bill and lost time while the motorcycle sits in a dealership’s service department. On the other hand, be realistic and do not attempt repairs beyond personal capabilities. Dealership service departments tend to charge heavily when working on equipment that has been abused. Some will not even take on such a job. Use common sense to avoid getting involved in a procedure that cannot be completed satisfactorily. If the decision has been made to refer troubleshooting to a repair facility, describe problems accurately and fully. Table 1 and Table 2 list electrical specifications. Tables 1-3 are located at the end of this chapter.
Perform the following spark test to determine if the ignition system is operating properly. CAUTION Before removing the spark plugs in Step 1, clean all dirt and debris away from the plug base. Dirt that falls into the cylinder will cause rapid engine wear. 1. Refer to Chapter Three and disconnect the spark plug wire and remove the spark plug. NOTE A spark tester is a useful tool for testing the spark output. Figure 2 shows the Motion Pro Ignition System Tester (part No. 08-122). This tool is inserted in the spark plug cap and its base is grounded against the cylinder head. The tool’s air gap is adjustable, and it allows the visual inspection of the spark while testing the intensity of the spark. This tool is available through motorcycle repair shops.
2