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  1. #1

    motor swap on a 95 750 to a 780 q's

    Hello all! I've got a '95 polaris 750sl. It's not your typical set up. I cut the hull on an even plane around the motor and jet and bolted it into my 16' flat bottom aluminum boat. It's more fun than I could have hoped for! Untill this past weekend, in the middle of the lake, the #3 piston decided it no longer wanted to stay in one piece. I've torn the motor apart and found that the whole thing needs to be rebuilt. The cost of rebuilding and just buying a rebuilt one are pretty close, so I'm just buying a new one. The thing is, like many others, I want more power. If I buy a 780 can I use the same motor mts, carbs, fuel pump, mag, exhaust, and elect. box?

    Hope you guys can help me out. And yes I will get some pics up.

  2. #2
    ryandi2's Avatar
    Join Date
    Aug 2009
    conesus ny!
    welcome to the hulk..

    post some pictures of your boat! sounds cool.

    some one that knows your "fugi" motor better will chime in soon

  3. #3
    Thanks bud. I'll try to get the pics I have up tonight.

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    Welcome to the Hulk.

    If you want to swap a 750 for a 780 you'll need:

    Rejet the carbs

    780 exh manifold

    780 CDI

    At least a triple outlet fuel pump, if not the pentagon H.O fuel pump that came stock on a 780.

    And maybe a bigger impeller to take advantage of the added power.

  5. #5
    Thanks for the welcome.
    New to jetski lingo, what's a cdi?
    I thought about the impeller, but would I need to factor in the added weight of the boat on impeller selection?
    Thanks for your input.

  6. #6
    seaobin's Avatar
    Join Date
    Jun 2007
    Raleigh, North Carolina, United States
    CDI is the electrical spark initiator. It controls the timing and spark for the engine.

    since you hull is larger you might have less weight to hull area ratio than a ski, hence a more aggressive prop

  7. #7

  8. #8
    Sounds like I'm rebuilding the 750 and porting it out, maybe go 1 or 1.5 over std

  9. #9
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    The CDI is basically the ignition "computer".

    I hadn't thought about the added weight of your aluminum hull. So the 750 impeller would prob be a good choice after all.

    Well, if you actually mean "porting" the 750 cyls, that's going to run around $500 to have done.

    Just going to an oversized piston will help a little, but not as much as you may think.

    A 750 makes 80 HP, while the 780 makes 92+ HP. And it's going to be more reliable.

    If you're really interested in beefing up that engine, I have a 780 engine package I'm selling. It has almost everything you'll need to convert your 750 to a 780.

    It'll need the cyls bored, wrist pin bearings, circlips, and a 780 CDI. That's it.

    If you want to stay with the 750, I have 1mm oversized Wiseco pistons and rings, as well as high compression heads if you're interested in those too.

  10. #10
    I can port the cylinders, that's not an issue. Shot me some prices on your 780 and the 750 top end stuff.

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