Home Forums TaG QUESTION FOR THE YEAR

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    • #16608
      Jim Silverheels
      Participant

      Anyone have any idea why I have gone through 6 Leopard rotor/commutators  this past season? I’m not talking brushes but bad commutators. Put the continuity tester on the commy and will always find a dead leg. Yes I have double grounds and positive the commy’s are bad. When I tap the starter it will take off but if it gets stuck in the dead position, of course it wont go on the starting grid.. thanks

    • #16613
      tony zambos
      Participant

      Jim,

      That sounds very unusual.  No ideas, but a couple of questions.  When you find the bad commutator, are you replacing just the commutator or the whole starter? And where, if you don’t mind, are you purchasing the replacement parts?

      LAD Specialties customer / tony kart / rotax / kt100

    • #16616
      Jim Silverheels
      Participant

      Tony, when the commutator goes I just buy a new starter. Don’t know if you can just buy a commutator. This has happened 6 times this yr. I’m positive there’s a dead leg on the commy. Once again did a continuity test on them. Yes it does seem unusual.

    • #16751
      tony zambos
      Participant

      Jim,

      Took apart a Leopard starter motor. Between any of the ten contacts, got about .7 ohms.  A couple of ideas. First, the insulation on the windings is melting do to extreme heat.  Possible causes could be too much current to the starter or maybe a poor ground.  Taking one of your busted starters apart and see if it smells like an electrical fire.

      The other possibility for the failure could be physical damage.  I’ll guess, since I have no proof, that if the motor was spinning without a load, that it could tear itself apart.  Could your starter motor still be running after the engine starts and the bendix has disengaged?

       

      LAD Specialties customer / tony kart / rotax / kt100

    • #16755
      Jim Silverheels
      Participant

      Tony,

      No sign of burnt wiring… I always ask myself what the most obvious thing to cause this and the answer is vibration or a bad ground. I have triple grounds and the armature has no visible breaks. Polished up the commutator also. Always a dead leg on these 6 armatures that are bad. Don’t have the answer, darn it.  thanks

    • #16776
      Ted Hamilton
      Participant

      Please post answer once you’ve found it…. you’ve piqued my curiosity.  I would’ve guessed faulty brush routing too much current through 1 comm leg or carbon bridging a comm leg…..  Be nice to know what to look for once I get my Leopard

      www.facebook.com/hamiltonhelmets/
      2014 Praga Dragon / IAME KA-100

    • #16786
      tony zambos
      Participant

      Jim,

      one last try.  Has the bendix ever been replaced?

      LAD Specialties customer / tony kart / rotax / kt100

    • #16793
      Jim Silverheels
      Participant

      Tony,

      No the bendix hasn’t been replaced. It operates very easily by hand when I took it out.

       

       

       

    • #16808
      tony zambos
      Participant

      Just a thought that the bendix might be  hanging up on occassion.  With the ring gear about four times the size of the bendix, the engine turning 3k would have the starter spinning at 12K.  We’re rooting for you.  Good luck and keep us posted.

      LAD Specialties customer / tony kart / rotax / kt100

    • #16992
      Tim Koyen
      Participant

      We replace our bendixes very frequently, since they seem overly prone to failure.  Perhaps Tony has a point?

      KartLift Kart Stands
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      Don't bother PMing me, it doesn't work. Email is best: tim@kartlift.com.

    • #17099
      Jim Russell, Jr
      Participant

      I have had several dead armatures over the years. If you spend the time you will find a broken copper winding wire somewhere in the mess. You can repair the wire and it will work fine till your repair breaks.

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