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Bore sizes

Discussion in 'XJ Technical Chat' started by Hamish Brown, Jan 10, 2019.

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  1. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Well, that makes sense, but actually Yamaha specifies it being done in the same manner (inside , working your way outwards), so I'm wondering where you are getting this info from? I would follow the Yamaha proscribed sequence, as they are quick to point out that you MUST follow the factory procedure, values, and tightening sequence when installing your cylinder head, as: THE #1 CAUSE OF CYLINDER HEAD GASKET FAILURE AND HEAD WARPAGE IS DUE TO IMPROPER HEAD INSTALLATION PROCEDURES!
     
    chacal, Aug 11, 2020
    #41
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  2. daphnebroon

    daphnebroon New Member

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    Thanks as ever, here is the manual I am using and the picture of the sequence in it. I will go on the premise that Yamaha and you guys know more about Yamaha engines than me and proceed with the advice and follow sequence below
    upload_2020-8-12_17-54-5.png upload_2020-8-12_17-54-36.png
     
    daphnebroon, Aug 12, 2020
    #42
  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Wow, you are correct daphnebroon, and I think that diagram is NOT correct, it is completely opposite from ALL of the other XJ/XS engines, which do indeed follow the "inside-out" sequence. Even the FJ600 manuals (which is basically a 550cc engine with larger jugs) show the inside-out sequence...........

    Hmm......I'll change my opinion and say to use the inside-out sequence rather than what the Yamaha service manual shows!

    ALSO:

    Note that the 12 cylinder head-to-crankcase stud nuts are torqued before the head-to-jugs nuts are torqued. The typical sequence (all except the XJ700-X water-cooled engines) is:

    1) the CYLINDER HEAD NUTS, center outwards in criss-cross pattern
    2) the REAR STUD NUT(S) on the cam chain tunnel.
    3) the two M8-SIZED REAR STUD NUTS (these are the fasteners just inside of the #1 and #4 intake ports on engines that use them…these are typically only used on “YICS” engines)
    4) the FRONT STUD NUT(S) on the cam chain tunnel.
     
    Last edited: Aug 13, 2020
    chacal, Aug 12, 2020
    #43
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  4. k-moe

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

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    Another mislabled photo appears to have been found.
    How many errors are we up to now in the various service manuals? 20?
     
    k-moe, Aug 13, 2020
    #44
  5. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    You're missing a zero............
     
    chacal, Aug 13, 2020
    #45
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  6. Minimutly

    Minimutly Well-Known Member

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    Hmmm, that would be for removal?? Ie removal and refitting are reversed sequence - are you sure you're not misreading it?
     
    Minimutly, Aug 13, 2020
    #46
  7. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Minimutly is absolutely correct...........the image shown above is the REMOVAL sequence, and the install sequence is the inside-out sequence.
     
    chacal, Aug 13, 2020
    #47
  8. daphnebroon

    daphnebroon New Member

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    Yes, I dismantled in this sequence but I can assure you the diagram is in the re assemble section of the manual.
    Luckily I asked you guys to confirm my instinct. I guess the manual writers just copied the dismantle procedure picture into the reassemble part.
    Anyhow I have torqued head down inside to out as everyone agrees this is the correct procedure.
    Thanks all once again.
     
    daphnebroon, Aug 15, 2020
    #48
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