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  1. #1

    785 PRO Engine Advice

    Hello everyone, im looking for a little insight into what avenue I should explore regarding a light overhaul on my 97' 785 PRO. I recently performed a compression test and found that the center piston is dead, upon removal of the cylinders, indeed the center piston rings were gone. Additionally i found scoring in all 3 of the jugs. I have tracked down a shop locally that can re nikasil plate my cylinder back to stock specs but im confused about what my best options for new pistons are. In the past I was able to find stock polaris replacements on ebay but now i cannot track any down. From the research that i have done, Weisco Forged pistons are available but the PWC must be warmed up properly every time and it makes it difficult to just start and go. I have also read that I could use stock WSM 750 SL pistons but I am unsure. Could anyone please provide me with some insight on what my best and cost effective option would be? Id really like to keep this ski going as it is a blast!

    Thanks!

  2. #2
    I'D RATHER SWEAT THAN SHIVER hyoctane23's Avatar
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    You've basically found the two remaining piston sources for our 785s...Wiseco or WSM. You'll probably never find another stock 785 piston unless someone has one laying around in their garage. I'd personally just run the 750 WSM pistons if your boat is stock or is a rec ski. Make sure you find out why your pistons got damaged so they don't do it again!


  3. #3
    Quote Originally Posted by hyoctane23 View Post
    You've basically found the two remaining piston sources for our 785s...Wiseco or WSM. You'll probably never find another stock 785 piston unless someone has one laying around in their garage. I'd personally just run the 750 WSM pistons if your boat is stock or is a rec ski. Make sure you find out why your pistons got damaged so they don't do it again!
    They are definitely getting hard to come by, I think ill go with the WSM pistons, just wasn't sure if i needed to change the rods to compensate for the different stroke.. Thanks for the info!

  4. #4
    rpa101's Avatar
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    Quote Originally Posted by JDMSiR View Post
    They are definitely getting hard to come by, I think ill go with the WSM pistons, just wasn't sure if i needed to change the rods to compensate for the different stroke.. Thanks for the info!
    the 750 pistons are your option
    before you send out your cylinders get the pistons and send them with the cylinders so they can give you the correct clearance
    and no you don’t have to change your rods

  5. #5
    Id really like to replace my crank seals while the cylinders are out getting repaired. What is the easiest way of changing them out? Do i have to remove the engine from the hull to do this job? Also does anyone know if the seals from a 780 SLX work?

    Thanks in advance!

  6. #6
    Hurricane1000's Avatar
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    Quote Originally Posted by JDMSiR View Post
    Id really like to replace my crank seals while the cylinders are out getting repaired. What is the easiest way of changing them out? Do i have to remove the engine from the hull to do this job? Also does anyone know if the seals from a 780 SLX work?

    Thanks in advance!
    Removing the engine engine and splitting of the cases is the proper method of replacing crank seals.....

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