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IH: Engine Control - Sub-01D

Magnavox Electronic Ignition Systems

(1980 to 2003) Components include a timing rotor (timing cup), sensor plate or inductive pickup, ignition control module, ignition coil and spark plugs. For electronic advance, the inductive pickup generates TDC pulses that are sent to the solid state Ignition Control Module (ICM). The ICM computes ignition timing advance and coil dwell. In 1983, a Vacuum-Operated Electric Switch (VOES) was added to switch between 2 different spark advance curves built into the ICM. 1)

  • This uses a Dual-Fire Spark system, using only one coil trigger wire to produce a spark on both plugs at the same time. (See coil information)
  • The spark advance start point can be altered by physically moving the sensor plate in the “nosecone”.
  • In May of 1980, the MoCo issued a Service Bulletin in response to having some owners of 1000cc and 1340cc engines, built since January 1, 1978, experience a knocking and / or pinging due to the unavailability of fuels with high enough octane ratings. Although retarding the spark advance will help to eliminate the knocking / pinging in an engine, a slight loss of power and fuel economy may be noticed by the owner. 2)
    • However, reducing the spark advance on these engines a small amount, anywhere between 1°-10°, can help to eliminate this problem.
    • Check the ignition timing to make sure it is set properly as described in the Service Manual.
    • Set the timing if necessary:
    • Start the engine and set the idle speed at 2000 rpm.
    • Retard the timing by shifting the timer plate counter clockwise in 2-1/2° increments until the problem is correct. Do not retard the timing more than 10°.
  • In February of 1981, the MoCo issued a Service Bulletin regarding the time intervals for initial firing with the ignition module. 3)
    • The electronic ignition modules have a protective control circuit that stops current flow to the ignition coil, if the engine is not running. This prevents overheating the ignition coil and limits the drain on the battery.
    • 1980 and E1981 ignition modules, with the part number suffix -80 (Sportster part number 32410-80 4) ), have a 4 second delay and will only start fir­ing on the second or third stroke. This causes a problem on kick-start motorcycles, where there may be a pause between kicks.
    • Newer modules, with part number suffix -80A (Sportster part number 32410-80A 5) ), have a 6 second delay and will fire on the first compression stroke.
    • Either module can be reset, if the protective circuit shuts off current flow, by turning the ignition switch or engine·stop switch off, then back on again.
    • The new modules will work in 1980 and E1981 applications without modification.


1)
1959-1985 Clymer Sportster Repair Manual pg 229
2)
HD Service Bulletin #M-780
3)
HD Service Bulletin #M-814 dated February 6, 1981
4)
1979-1980 HD Sportster Parts Catalog pg 23
5)
1979-1982 HD Sportster Parts Catalog pg 31
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