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1983 XJ750 Midnight Maxim - Oil plug

Discussion in 'XJ Technical Chat' started by steelrain121, Sep 8, 2019.

  1. steelrain121

    steelrain121 New Member

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    20190908_151133_HDR.jpg 20190908_151139_HDR.jpg Howdy! Super basic question, I just inherited this bike after it sitting for about five years. Dropping fluids etc for a start, but cant seem to get the oil plug out. Its got a thing in the middle ive never seen before, anyone have any insight? The bolt head is 19mm if that matters.

    Ill be searching more for other threads, but any general
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    some of the drain plugs have a screw in the center of them I belive it was for a temp probe

    6 point socket ONLY to remove the plug spray some penetrating oil on it

    it was put in with 31 ftlbs torque and a crush washer.

    long extention and a long breaker bar works for me. not a plain ratchet.
    you are going to have the same issue with the filter cap bolt,

    you may want to drop the exhaust if the exhaust nuts are not frozen again plenty of penetrating oil
    I have grown fond of (aero) Kroil works better than pb blaster
    https://www.amazon.com/s?k=areo+kro...585387&tag=googhydr-20&ref=pd_sl_6yhcqt4j2f_e




    I get mine at Napa auto parts you have to ask for it. something on can about not for sale to public.
     
    Last edited: Sep 8, 2019
  3. steelrain121

    steelrain121 New Member

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    Thanks much!

    More grunts shall be applied to the problem ha
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    kroil.PNG psst.. know where I can score some K dude?
     
  5. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The 50/50 ATF and Acetone mix works for everything.
     
  6. tabaka45

    tabaka45 Well-Known Member

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    My problem with the 50/50 mix is that the acetone evaporates before I get to use it all. But it does work.
     
  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    I mix what's needed, when needed. Any extra goes into a steel coffee can with a tight-fitting lid. I had to recycle a pint of it that had been sitting for a year (no evaporation).
     
  8. Kalikiano Kalei

    Kalikiano Kalei New Member

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    Regarding that Seca oil sump drain plug, I've encountered questions from others numerous times about that 19mm iteration bolt with the screw-inset on it. Most are uncertain what it does (several non-Yamaha forums voiced the opinion that it was added by a previous owner, for reasons unknown) and the question frequently arises: "What does that #$@&^%! screw do?" I believe XJ550H had it correctly with the observation that it was for a temp probe, but I've never found that fact verified anywhere in the technical literature about it. I'm guessing that perhaps a temp probe transmtter might have been fitted there as an option and what better place for that than smack in the middle of that plug? Otherwise, it seems to serve no functional purpose whatsoever, as far as I can determine. I'd love to have some wizened old Yamaha factory technical person verify that, but I'm not holding my breath.

    What I do know for a fact is that all SECAS (XJ550 through XJ900 SECAS) for the US market came originally from the production line with that bloody inset-screw on the drain plug (that plug has, of course, a magnetic component to catch engine metal shavings). Both my old XJ550 and XJ750 SECA had it. Most were replaced by owners with a standard bolt of the same thread-size, but with a slightly smaller 18mm bolt head. To this day, folks who have found and acquired a vintage SECA puzzle over the plug (with the screw), if it still has its original plug (most do not). I am uncertain about Maxims, but I'd guess they originally came with that same screwy OEM plug, as well.

    One last thing: I once had a fellow swear to me that that that screw was there to help keep the plug from vibrating loose :))).

    Another interesting and arcane vignette from SECAville!
     
  9. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    My Seca 750, and the 65o Maxims that I've worked on, had the standard oil drain plug (and I know of one member who has had the standard drain plug from new). The FSM also pictures the standard drain plug, and that was written using a new production bike.
    As with many other small details, what was on hand at the time of assembly was used. The differences in noncritical parts is often the result of the legislated sharing of parts amongst all Japanese manufacturers.

    Also recall that there was a plethora of aftermarket parts available for the range, and fittings for temperature probes were (and still are) a common aftermarket item.
     
    Last edited: Oct 14, 2019
  10. XJ550H

    XJ550H Well-Known Member Premium Member

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    your drain plug has a screw in it? the screw is for testing. it is removed and a temp probe is put in the hole or one is screwed onto the screw
     
  11. kerriskandiesinc

    kerriskandiesinc Active Member

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    I THINK my 750 (imported in to UK) '91 Maxim had the screwy thing.....and all? of my Euro/UK XJ's did NOT have it ( but then again, at least they were provisioned with the standard XJ oil cooler, whereas NON of my American ones, including the Maxim were !!)

    As far as I can remember, a lot of 80's Japs had a magnetic drain plug......a great idea, as mine has always caught quite a bit of swarf during oil changes !!
     
  12. cgutz

    cgutz Well-Known Member

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    My '82 Maxim XJ550 has the screw in the drain plug. I am the original owner, and original bolt. I too always wondered what it was for...
     
  13. Polock

    Polock Well-Known Member

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    are there plugs with a magnet that don't have a screw?
     
  14. XJ550H

    XJ550H Well-Known Member Premium Member

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    could be as simple as the screw holds in the magnet.

    screws or not my plugs all have magnets
     
  15. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Mine is like that....I think.

    Now I'm unhappy that the bike is not here.. thanks :p
     

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