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Repairing relays

Discussion in 'XJ Technical Chat' started by joejr2, Sep 14, 2023.

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  1. joejr2

    joejr2 Active Member Premium Member

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    I completed my xj750seca project, looks great. I'll post pics soon. Anyway, I have an xj650 that I almost finished a couple of years ago. The starter button
    went dead and I shelved it for a while. Last week I started in on it again. Having
    researched the circuits, switches, relays etc. that make up the ignition system,
    I used a multimeter to narrow the problem to a faulty cutoff relay. Out of a
    box of salvaged relays, I only found one that works and only intermittantly.
    Can these relays be pulled apart and repaired ?
     
  2. Rooster53

    Rooster53 Well-Known Member Premium Member

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    I would say yes some can. If the cover is removed you can look for corrosion causing problems with the movement or with the contacts.

    If the internal diode is bad in the starter cutoff relay it is quite difficult to replace. I don't have a spare headlight relay, but likely tough to do that diode also.

    If the coil is open then it's toast unless you can spot a broken enameled wire

    If there is lots of corrosion it might be best to just scrap, particularly the side stand relay that could kill ignition at a very inconvenient time

    upload_2023-9-14_17-29-23.png
     
  3. joejr2

    joejr2 Active Member Premium Member

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    Sometimes the starter button freezes. If I pull the cutoff relay from its connector, tap it against the bike frame and put it back, the button will activate the starter again. does this indicate fouled contact points inside the relay ?
     
  4. Roast644

    Roast644 Well-Known Member

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    I wonder why Yamaha used a diode in the cutoff relay rather than adding it the the diode block or using an inline diode as they did elsewhere. That would have simplified the number of relays and made replacement easier 40 years in the future!
     
  5. Rooster53

    Rooster53 Well-Known Member Premium Member

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    It could, but my first thought is the mechanical mechanism is corroded creating enough friction that it is difficult for the electromagnet to overcome that. Either way, a relay like that is useless so if you carefully pull the cover you will get a better idea of what is wrong. Once the cover is removed you would see if you can free the mechanism as well as clean those normally open contacts.

    Not sure why, but hard to imagine they didn't decide on what they thought would be the most profitable in the end
     
    Roast644 likes this.

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