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  1. #1

    657 to 657x conversion question(s)

    As far as I could tell, this has not been asked ....

    If I have a completely good 657 and also a 657x with mostly bad internals, what would need to be mated up from the two to make a good 657x?

    Is the crank case the same/different?
    Are the Cylinders the same/different?

    The only thing I have seen for certain was that head is different, due to deck height.
    Is that caused by the crank case or cylinders or both.

    Hopefully someone knows ...

    Thanks


  2. #2
    "Hustler" Inkaddict's Avatar
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    Quote Originally Posted by ranman View Post
    As far as I could tell, this has not been asked ....

    If I have a completely good 657 and also a 657x with mostly bad internals, what would need to be mated up from the two to make a good 657x?

    Is the crank case the same/different?
    Are the Cylinders the same/different?

    The only thing I have seen for certain was that head is different, due to deck height.
    Is that caused by the crank case or cylinders or both.

    Hopefully someone knows ...

    Thanks

    If I remember correctly the porting on the cylinders is the only difference...

  3. #3
    Thanks.

    Anyone else have some input?

    Does anyone have a parts catalog for any of the following:
    94 SPX
    94 GTX
    93 XP

    So I can cross-ref 657 part numbers to the 657X numbers.

    X Cylinders are 290913388
    X Head is 290913706
    X Cases are 290887222

  4. #4
    flyin' the friendly skies airbornexp's Avatar
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    your stators are differnent also I believe. there was a guy on here that had a jet boat with one 650 and one 650x ans was having problems getting the motor wired up.

  5. #5
    Thanks for the info on the stator/magneto.

    From what I have found, I think it may depend on the year of the 657 as to the Stator being different. I cross-refd and got the same part number on the Magneto for both the 657 and X ... but the 657 and 657X were the same year - 95. So ...

    I have found some more info ....
    So here goes ...

    X Cylinders are 290913388
    X Head is 290913706 (? - New # may be 420913706)
    X Cases are 290887222
    X Rotary Valve 159 Deg is 290924502 (? - New # may be 420924502)

    What I have found for 657 numbers so far:
    Cylinders are 290913386
    Head is 290913701 (? - New # may be 420913706 ... new no. same as the X, unlike old no.)
    Cases are 290887222 (? - New # may be 420887222)
    Rotary Valve 147 Deg is 290924508 (? - New # may be 420924508 )

    So ...
    The Rotary Valve (but that's more of an external piece) are different deg ...
    And ...
    It looks like Cylinders and Head were different.
    But now with the new part # the 657 Head supercedes to the same part #.
    (Hmmm, not sure I trust that).

    Any thoughts on the Head?

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