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G15: set the ignition timing with magneto

Discussion in 'Other Norton Motorcycles' started by pierodn, Oct 27, 2018.

  1. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    It is my first time with magneto.
    Please, could you explain me (in easy way) how set the timing with magneto.
    I usualy work with the points distributor on the back.
    Thank you.
    Piero
     
  2. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Do you have the manual open in front of you?
     
  3. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    Do you know how to use a timing disc and a mechanical stop to find top dead center (TDC)? I think Texas Slick has detailed timing instruction if you search this site.
     
  4. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    I have only said that is my first time with magneto.
    Sorry but my twins and triples engines rebuilt by me run all great.
    Repeat, i need to understand how set the magneto timing not how to serach the TDC and come back of 30/35 degree.
    How to set the point at BTDC, this is what i need to understand.
    If you dont know, dont answer.
    Piero
     
    Last edited: Oct 27, 2018
  5. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
  6. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi.
    My Workshop manual says only how clean magneto point and to check the gap.
    May be yo have not read well.
    Piero
     
  7. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Slick,
    thank you so much for sending me your topic link.
    Certainly is clear but sorry i am not a mother language so that was easy lost me in translation.
    If i can summarize what i have understood, considering that my magneto is in place:
    - starting from TDC i rotate back the engine of 35 (or 30) degree.
    Then i am not sure what i have understood, not usually with magneto and translation.
    Thank you.
    Piero
     
  8. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
  9. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Piero:

    1) Check point gap is equal on both ramps .... this is very important! If not equal, do Steps #2 to #6

    2) Find TDC (Step # 7 and #8) Step #9 does not apply to you.

    3) Do Step #10 and Step #11. There is nothing special about 35 degrees .... rotate backwards past your target timing set point.

    4) Do Step #12 to #17.

    Se c'è qualche passo che non capisci
    , PM me.

    Slick
     
  10. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    I’d be more interested in equal timing than equal points gap .
     
  11. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Equal point gap yields equal timing if the cam ring is spot on CNC machined. Refer to Steps #15 and #16 in my tutorial.

    Slick
     
  12. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Slick,
    Thank you again.
    Sorry, but step 13 is not clear for my capacity.
    Could you kindly explain in easy way?.
    Thanks for helping me.
    Piero
     
  13. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Yes. There’s an “if” in that sentence.
     
  14. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Piero:

    In Step #13, VOM is Volt - Ohm - Meter. If you do not have one, I suggest you buy. They are not very expensive, and you will find helpful for electrical testing. If you have one, good.

    Set the VOM function to "Ohms" and select maximum sensitivity .... this is the setting that usually makes "beep" sound when lead (probe) wires are touched together. Then connect probes using "alligator" clips to the places A1 (or A2), and B in the Figure under Step #6.

    If you have done all the steps before Step #13, the VOM should "beep". The beep indicates the points are closed. Points should be closed if engine is backwards 35 or more degrees from TDC, and the long screw that secures the contact block is not installed.

    Now slowly rotate the engine forward until the beep stops. This is the place where the points open, and the magneto fires. Make a note of this place on the degree wheel.

    Next, Step #13 says repeat several times to check your work.

    PM me if you need more help.

    Slick
     
  15. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Hi Slick,
    I will try.
    Sorry, but can i use a light to check that the point open?.
    But may be not because there is not power from battery?
    Thank you.
    Piero
     
    Last edited: Oct 28, 2018
  16. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    You can use a test light with a battery, if the centre screw is loosened or removed.

    Or you can use a cigarette paper or similar thin piece of material, held between the points. Feel for when the points lose their grip on the paper: that is the points opening.
     
  17. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Be advised that using paper changes the timing set point by 2 degrees for each 0.001 inch thickness of the paper. I have measured this effect. Ciggie paper is about 0.005" and results in a 1 degree change (toward more advance). This is insignificant, but some "thin" paper can be nearly 0.002 " resulting in a 4 degree change.

    Slick
     
  18. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Yep definitely, but it’s a way to set your timing.

    Whichever way it’s initially set, checking with a strobe is a good idea, if you’re interested in how the timing really behaves when the engine is running.
     
  19. pierodn

    pierodn

    Joined:
    Nov 10, 2012
    Strobe?
    The only way i know and i use is with a degree wheel on the cam timing side rev count.
    Piero
     
  20. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    You can put a timing mark on the alternator rotor and attach a wire pointer to the engine, or mark the stator as well.