Need educated

Discussion in 'Touring Models' started by stevec314, Mar 11, 2010.

  1. stevec314

    stevec314 Member

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    Just wondering. I know that on some of the really old bikes they had a timming advance. What came along later that eliminated the need for this??

    Steve
     
  2. Hoople

    Hoople Account Removed

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    A Map in the ECM.. still has advance but is done electronically
     
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    The automatic timing advance was a set of pivoting spring loaded weights usually sitting behind the points backplate as the engine speed got faster the weights would be forced outwards by centrifugal force however that force was controlled by the springs as the weights moved then they would adjust the ignition timing by advancing or retarding dependant on the engine speed
    But things have moved on since then

    Brian
     
  4. Breeze3at

    Breeze3at Well-Known Member

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    I know I'm gonna miss several "generations" of advance mechanisms but:
    *First was a cable from the left grip to the distributor, twisting advanced and retarded the spark.
    *Then "flyweights" or "bobweights" were fitted to the distributor rotor. As they spun, centrifugal force pulled them out to change the timing with rpm. springs returned them as rpm's decreased.
    *The first electronic ignitions had 2 slots in the rotor that controlled the advance (magic in my unlearned mind).
    *Next gen. electronic ign. used a VOES (vac.oper.elec.switch) to advance the timing according to intake manifold vacuum.
    *Twin cams ignition timing is controlled by ECM and hundreds of variable signals from various sensors (SERIOUS magic to my unlearned mind).:laugh
     
  5. Chopper

    Chopper Senior Member

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    Yea, what Brain said, then it went to the VOES system electronically advanced by manifold pressure & ignition modules and then into the ECM map still reading sensors doing it electronically like Hopple stated.
     
  6. stevec314

    stevec314 Member

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    Great stuff guys. Great history breeze! Printing this out to take it to the guys in the back.
    Thanks

    Steve
     
  7. Gator454

    Gator454 Active Member

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    It was never eliminated, just technology replaced it with a newer and better method.
     
  8. 67wizard

    67wizard Junior Member

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    Breeze3at is it knowledge or old age showing?

    I don't feel so bad now if its age showing.