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Can maladjusted timing cause coils to get hot?

Discussion in 'Norton Commando Motorcycles (Classic)' started by jimbo, Aug 22, 2019.

  1. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    Both of my coils get hot after running a while, I would say about 140* ( pretty hot but doesn't burn your fingers). Would retarded or advanced timing cause the coils to get hot?
     
  2. dynodave

    dynodave

    Joined:
    May 28, 2003
    No, not from early or late timing. Only indirect heating to coils might be from proximity to engine itself. The majority of coil heat is from electrical drive current .
     
  3. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    Thanks for the quick response.took the roadster out for a compare its coils got warm but not as hot as the interstate, but I might have had the inter idling longer. Trying to figure out the Interstate's tendency to die at idle when warm (lots of potential issues there!)
     
  4. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    As DD said, timing has no effect on the coil itself but coils can go bad in very strange ways. I once worked on a car where the ignition would cut out on aggressive left-hand turns. It wouldn't do it in any other mode and wouldn't do it in a normal left turn. It was the coil! Talk about troublesome to diagnose... ;)

    I know, you may be thinking that it wasn't really the coil, maybe a connection that was corrected when we replaced it. NOPE, we installed the same coil in the same orientation in another car and the same thing occurred. Bizarre!

    We kept it on the shelf with a sticker that said "OK for right turns." :)
     
  5. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    Wow! I think I had a coil messin with me on the Scott I had, after strandin me on a hilly road,pushing up the hills and coasting down trying to start it.After a few miles of that it started up. o_O

    However on the Interstate both coils were the same temp so both failing at the same time is unlikely .
     
  6. Danno

    Danno

    Joined:
    Feb 7, 2010
    Carbs go lean when hot and EFI tends to go rich, which is why you have to have the leg of a t-rex to fire a hot, hi-comp single like a BSA Victim 441. If your slides are a little loose, or the float height is a little low, it may be sucking a bit too much air, but only at idle does the lean out overcome the flywheel. The extra warmth could be from a slightly leaner mixture.
     
  7. HRD

    HRD

    Joined:
    Mar 21, 2011
    Are you using 6 volt coils ? If so is the ballast resistor working correctly.Have you measured the voltage to the coils.
     
  8. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    same coils & ign setup for 20yrs
     
  9. marshg246

    marshg246 VIP MEMBER

    Joined:
    Jul 12, 2015
    Assuming you still have points, a shorted/partly shorted ballast resistor could make the voltage too high at the coils. Just measure the voltage to ground on both sides of the ballast resistor - one side battery voltage, the other side approximately 6 volts. Too high a voltage or shorted coil, but since both are doing it, I suspect too high a voltage. Also possible that the regulator/Zener is bad and you overall have too much voltage at higher RPMs.
     
  10. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    nope... electronic, lucas rita had it for twenty years

    higher revs are A-OK
     
  11. ashman

    ashman

    Joined:
    Jul 11, 2010
    Coils do get hot and usualy when a coil goes bad they get very hot and will cut out when they over heat but will run again once cooled down till they get hot again, this happened to me a very long time ago and took a while to work out it was a bad coil once I replaced the coils all was good again, at the time I just replaced both coils with another set I had.

    Ashley
     
  12. Onder

    Onder

    Joined:
    May 11, 2010
    Since you have other bikes changing out the coils for known good might be useful even though being a parts changer

    seems a bit lame.
     
  13. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    After 20yrs you would think that the system has been flogged to death, and wants to go into semi-retirement- you really need to get a complete electrician test of the whole system by someone who knows the ins and outs.

    Maladjusted timing can cause piston trouble –don’t ask me how I know!
     
  14. jimbo

    jimbo VIP MEMBER

    Joined:
    Sep 25, 2004
    I have been eyeing a Tri Spark for the better/ more like points ign curve and idle stabilization ....
     

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