Ignition Coil


The ignition coil is a pulse type transformer that transforms or steps up low battery voltage to the high voltage necessary to jump the electrode at the spark plug in the cylinder head. Internally the coil consists of primary and secondary windings with a laminated iron core and sealed in waterproof insulating compound. The ignition coil cannot be taken apart or coil repaired. If the ignition coil is defective, it must be replaced.

CAUTION — On 1980 and later models, use only ignition coils marked ELECTRONIC ADVANCE. On 1979 and earlier models, use the old style coils. Interchanging these coils could cause a failure in the electronic components.

Transfer terminal wires to new coil as shown in wirinc diagram for that particular model.

CAUTION — Connect ignition coil wires as shown in wiring diagrams. Reversing polarity to the ignition control module will permanently damage the control module.

Attach new spark plug cables to coil and plugs. If ignition trouble is eliminated by the temporary installation of new coil, carefully inspect old coil for damaged cables and insulation. The insulation on cables may be cracked or otherwise damaged allowing high tension current to short to metal parts. This is most noticeable in wet weather or when motorcycle has been washed.


When engine will not start or when hard starting or missing indicates a faulty ignition system, follow the troubleshooting procedure listed under the respective ignition system sections. If condition persists, check primary and secondary resistance of ignition coil with an ohmmeter. Resistances should be within the following limits:

1979 and Earlier

Primary 4.7 to 5.7 Ohms

Secondary 16,500 to 20,000 Ohms

1980 and Later

Primary 3.3 to 3.7 Ohms

Secondary 16,500 to 19500 Ohms

If a coil tester is not available, temporarily substitute a new ignition coil by attaching it at any convenient point near old coil (coil will function without being securely grounded).


Resistor type high tension cables are used. This type has a carbon impregnanted fabric core instead of solid wire for radio noise suppression and improved reliability of electronic components. For this reason, it is recommended that the exact replacement cable is used.

Remove old cable from coil terminal and install new cable. Always be certain that cable boot or cap is securely tightened to the coil tower to prevent moisture and dirt from contacting the high tension lead. Replace boot or cap if damaged or loose fitting.

CAUTION — When disconnecting cable connector from spark plug terminal, do not pull on the cable itself because the cable carbon core will be damaged. Always pull on the rubber boot as close as possible to the spark plug terminal.

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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