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650-650X What's the difference?

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  • #16
    Re: 650-650X What's the difference?

    if the motor was ported right its very possable . its a light ski and the old doos crank with some porting work done :-) ya never know untill you rip it apart lol
    PRIDE IN SERVICE<br /> <img src="http://www.sbtontheweb.com/images/forposts/4609/1.jpg" alt=" - " />

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    • #17
      Re: 650-650X What's the difference?

      I think I'll rip it apart! NOT! As long as it's running they way it is now I'll leave it alone. With the age of this ski it could break tomorrow. I'll ride it until then the way it is. Maybe after the season I'll get a new one. Any suggestions on what to buy. I like speed but am not a very good mechanic. As far as stock bikes what do you recommend?
      Attached Files
      skimanic@wolf-ridge.net
      "94 XP"
      Wolf-Ridge.Net

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      • #18
        Re: 650-650X What's the difference?

        Without a pipe, you're only getting a handful of HP from internal porting and boring. If that was done and a steep impeller was used, I can see top-end being up there at the expense of low-end, but it would take a while to get there.
        SBT Tech Support is here to help with your problems.
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        • #19
          Re: 650-650X What's the difference?

          Just to make sure my GPS wasn't off I used my brother's Garmin GPS. Still shows 55-57 mph. What mods could have been done to the engine?
          skimanic@wolf-ridge.net
          "94 XP"
          Wolf-Ridge.Net

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          • #20
            Re: 650-650X What's the difference?

            you might have a groupk type performance package already done! if it runs that fast then there is somthing definatly done to it.

            657x motors were made TWO years and came in the 94xp, 95spx, and the 95gtx as well according to my doo doo book. there were other different things as well as the internal stuff that was mentioned above. they had twice the spark power of a stocker, larger twin 40's similar to the 720, motor was set up much looser according to the doo doo book and if you look at the exhaust system, those style exhaust only came on a handfull of skis, 94xp, 95spx, 95gtx, and the 95xp 720 platforms, oh yeah, and the 720 hx skis. those exhaust systems (which are bigger than the stockers) are suppose to give more bottom end. if you look at the waterbox too, you will see that it is cupped inwards to make it shorter too. those style waterboxes only came on the skis with that exhaust system. if i could only stuff a 657x motor setup in my kawi 550 id die a happy man.

            groupk is known for there "sleeper" type mods that look totaly stock, sound stock and start like a stocker. id do a compression check and make sure you dont have to run 91+oct in it. groupk likes to modify the stock existing pieces on your boat and the 657X already comes pretty tricked out from the factory. if its that fast then id leave it alone or upgrade your cc's if more speed is desired like as in a 96xp w/groupk mods.

            if it has been wammied by someone like group k then expect the cylinders to be ported, head to be milled and re-cut, carbs to be bored and internal circuitry upgrades as well. but you'll never know till you take it apart.
            cameron "da river rat"<br />3x pro runabout 720 engine blower!<br />(jetskianist~adictionist~modificationist)

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            • #21
              Re: 650-650X What's the difference?

              Dude, that 94 is Kickin'. Sounds like a fun boat.

              Steve

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              • #22
                Re: 650-650X What's the difference?

                I checked the compression. 152 psi on each cylinder. I'm already running 93 octane. I did find out that the VTS was not connected and haven't ridden since I fixed that. I won't tear it down unless it blows. I'll just enjoy it while it runs. I get a lot of looks when I pass up some other skis on my old 94.
                skimanic@wolf-ridge.net
                "94 XP"
                Wolf-Ridge.Net

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                • #23
                  Re: 650-650X What's the difference?

                  What are specs as far as RPMs for my 94 XP? I think I read at WOT it should be ~6200. I've been hitting 7100-7200 on flat water. BTW...after repairing the VTS the ski handles great! No bouncing and lots more bottom end thrust.
                  skimanic@wolf-ridge.net
                  "94 XP"
                  Wolf-Ridge.Net

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                  • #24
                    Re: 650-650X What's the difference?

                    6750 + or - 50 rpm is the normal rpm.
                    Bill O'Neal <br>
                    WCM
                    <a href="http://www.watercraftmagic.com"

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                    • #25
                      Re: 650-650X What's the difference?

                      Well I gave up trying to figure out why this ski seems to perform better than the stock 94 XP. I called the previous owner who lives about 10 miles from me. His son Silas was into racing a few years back. (He was a Survivor Series competitor) The formar owner told me that his son took the ski to our local Sea Doo dealer, who also has a racing team, and asked him to modify the ski for racing. This was in 1997. The former owner said that he couldn't remember what was done at the time, but that the bill was around $1500.00. He said that the dealer mentioned that he should get 7-10 more mph with the mods the he bought. I guess this explains the better performance! What could have been done to the engine. Would a modified flame arrestor and modified pipe make this much difference? The former owner did mention that he was told to pre-mix AV fuel and 91 octane. Why is this necessary? I also looked at some Iridium plugs. Are they better than the R's?
                      skimanic@wolf-ridge.net
                      "94 XP"
                      Wolf-Ridge.Net

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                      • #26
                        Re: 650-650X What's the difference?

                        with only 152psi i would'nt worry about anything but 87. that compression is fine for low octane but if your worried then you can run the better grade. with that low of compression, it would be very hard to achieve that much speed out of carb boreing/modifying, cylinder porting (would have to raise compression), and water injection possibly? i just cant see a 657x going that fast w/o some major mods but who knows??????
                        cameron "da river rat"<br />3x pro runabout 720 engine blower!<br />(jetskianist~adictionist~modificationist)

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                        • #27
                          Re: 650-650X What's the difference?

                          I have a 94 XP with the 657X motor in it too. The only thing I have done to mine is an r&d intake grate. One thing I don't like is that it porpoises so bad. I had a 93 xp and this one is a lot faster. What about a ride plate or impeller?

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                          • #28
                            Re: 650-650X What's the difference?

                            I have a nice rideplate extension for that model $75.00

                            There isn't an impellor for a stock 94 that yeilds alot more speed than the one that came on the ski, although the Solas impellors are pretty good for speed, but not much better. I sell those for $165.00
                            Bill O'Neal <br>
                            WCM
                            <a href="http://www.watercraftmagic.com"

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                            • #29
                              Re: 650-650X What's the difference?

                              Is your VTS working properly? I thought mine was but when I checked the nuts that hold the cable on the slide housing at the trim motor were off. Once fixed I had almost no porpoising.
                              skimanic@wolf-ridge.net
                              "94 XP"
                              Wolf-Ridge.Net

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                              • #30
                                Re: 650-650X What's the difference?

                                Originally posted by Bill O'Neal2
                                I have a nice rideplate extension for that model $75.00

                                There isn't an impellor for a stock 94 that yeilds alot more speed than the one that came on the ski, although the Solas impellors are pretty good for speed, but not much better. I sell those for $165.00
                                Bill, Is the ride plate still available and how much trouble to put it on? Does it effect bottom end?
                                skimanic@wolf-ridge.net
                                "94 XP"
                                Wolf-Ridge.Net

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