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  1. #1

    Big bore 750 project.

    So I bought a project boat last winter 95 sl750 cheap and needless to say need to overhaul the engine... done that all ready on my 94 no worries as the bores were all good and everything went back to stock. When I went to wiseco's website I saw they had piston kits going all the way out to 2.5mm over size that would be almost 800cc displacement... can the stock jugs be bored out that far? Also what other problems would I run into doing that? I don't have a lot of experience with two stroke engines and really think this would be fun to try.


  2. #2
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    For the gains, I wouldn't go any bigger then needed. If you go max and ruin a cylinder, it's junk then. You could get better gains in speed with different ride plate, extended pump, pro 785 cdi, and other mods. But even with them, it's still a 750 triple.

    More speed....Go with a bigger motored ski to start with. Alot of the older ski, you'll drop more money trying to go faster then you could ever get close to getting back out of it...trust me,I know all too well, as many others on here know from just a few years ago.

  3. #3
    OK so I'm a really big guy even so I have gotten 48 according to the iPhone out of my 94 but that's all I can seem to get out of it, it has no oomf if I let off then try to pick it up to turn quick but will scoot just fine straight or relatively close to straight. So what would be the best options then when putting this ski together then to get that mid range oush. I know its not entirely me being a big guy because my friends 750 converted 650 picks JP and goes anywhere with me on it except out of the hole.

  4. #4
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    A set of sponsons will help get on plane better. And a Pro 785 CDI will give you more advance in timing and alittle higher Rev limiter. Stepping down a pitch on the prop would help with getting the RPMS up quicker, but cost speed. I would try the CDI and Sponsons first,(actually cheap upgrades) check how your prop and pump stator looks, nicks, busted vains ,ect will hurt you all around.

  5. #5
    RLACEMAN's Avatar
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    A set of 780 reed spacers & a 780 flame arrestor will give you more than boring the cylinders, I agree with keddano, don't overbore anymore than you need to. Also for acceleration & a little more top speed a skat-trak 13-18 impeller with help out alot, I use this impeller on my SLT with good gains, I may also try a Solas 12-18 this summer to see which works better.

  6. #6
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    The Boyesen Pro series reeds really woke up my 650. Im sure it would help a 750 too

  7. #7
    RLACEMAN's Avatar
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    They may help, I know Vforce reeds do nothing, I put a set of those in & no change in acceleration & top speed rpm remained exactly the same, I was very dissapointed. However years ago I put them in a 1050 motor & got good results.

  8. #8
    Thanks guys! I got a few things to track down now for when I start building her up.

  9. #9
    Sorry to bother you guys with another "what if"question but is a water box necessary or can a shielded through hull be installed on one of these? My friend made custom pipes for his snow machine and said he would help if I wanted to try it on a ski. the cardboard monstrosity he mocked up though would have to fit right where the current water box is. This is just a "for fun and can we do that?... (aka probably a fruitless money pit)" project now since I got another Machine going anyway..

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Removing the waterbox would provide a lot more noise, not much else.

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