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Lucille pulls another one on me....

Discussion in 'The Garage' started by MaxPete, Jul 30, 2018.

  1. Paul Sutton

    Paul Sutton Still Looking Good Top Contributor

    Thank you TM regarding Silicone. I have the thin spray stuff for locks and the thick vacuum grease for plastics and electrics. I had a voltmeter that lasted 2 startups. I bet the inductive spike from the rotor got to it. When testing my rotor by measuring its current drain I was surprised how big the induced spark was when I removed my temporary power wire. So I installed a diode across the brushes in a similar manner to TM. Here is his thread on the topic:
    Thank you again TM.
    TwoManyXS1Bs and MaxPete like this.
  2. jetmechmarty

    jetmechmarty What should I put here? XS650.com Supporter Top Contributor


    Dielectric grease is an insulator. It stops electrons better than it stops water.

    Only a little under the spark plug boot.
    MaxPete likes this.
  3. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Yes, that's the idea. Protects connectors from the elements, and prevents electrons from escaping their cages, to wander off and create electrolysis, and other carnage.

    Definitely avoid conductive greases.

    With non-moving high friction/pressure contacts, like bullet and spade connectors, the metal-to-metal electrical contact is assured even when drenched in dielectric grease.

    Also works well with sliding contacts, like rotating ignition, headlight, and turn signal switches.

    Not so with flat-faced landing contacts, like points and relay contactors.
    Don't use it there.

    Been in standard use for a long time, like with old vacuum-tube TV sets.
    The early contact dopes (before silicone) predate me.

    Standard automotive use since the '80s, especially in the firewall bulkhead connectors.

    If the environment is dry and sterile, it's not needed. If the contacts are lightly loaded, and handle low voltages and currents, it's not recommended. Absolutely keep it away from avionics trays and their edge/pin connectors.

    Google "dielectric grease spark plug" for application info...
    Last edited: Sep 17, 2018
  4. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Riding a bike with a hot engine, then hitting rain and water, the rapid cooling can pull moisture into trapped spaces. Take the XS650 to the carwash, and spray the engine before it's cooled. Roll it out, dry it off, then pull the points and advancer covers. There'll be some condensation in there.

    Spark plug caps also get hot, and have trapped air, which can pull moisture into the caps when rapidly cooled.
    PlugCap01.jpg PlugCap02.jpg

    The rubber boots are supposed to prevent moisture entrainment. The dielectric grease ensures the seal...
    Paul Sutton and robinc like this.
  5. 5twins

    5twins XS650 Guru Top Contributor

    Yes, when I put dielectric grease on my spark plug wire ends, I also run it up the sides of the wire on the insulation about 3/4". Then the rubber boot slides down onto it and I figure this gives me a double seal (rubber boot and silicone grease). I also put a little on the end of the cap or coil where the rubber boot fits onto.
    TwoManyXS1Bs and robinc like this.
  6. 5twins

    5twins XS650 Guru Top Contributor

    Using one of your pics as an illustrated example .....

    Paul Sutton, TwoManyXS1Bs and robinc like this.
  7. jetmechmarty

    jetmechmarty What should I put here? XS650.com Supporter Top Contributor

    With the exception of spark plug boots, I am, and shall remain a staunch contrarian to the use of dielectric grease.

    Bullet connectors are engineered to be a one use item. Ford wants me to buy a new car in less than 10 years. In our hobby, that stuff will bring grief.

    Rather than carry on a lengthy discussion, I respectfully disagree with its use based upon my own knowledge and experience.

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