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  1. #1
    bowsniper's Avatar
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    Stroking the Pro?

    I heard from a guy today that you can stroke the 785 pro 2.2 mm's and make it even more powerful. I think he said it would be 840 cc or something along those lines. obviously bigger displacement. then he said sleeving is fine with them.. you dont need the nicasil coating either.. is he crazy?

    kinda sounded like he knew what he was talking about. he owned a couple 900zxi's and 2 standups.550's..


    he also was saying that the pro died out of interest because of the price, he said you could buy one up in canada when new for 5500.00 american..

    the 2000 Pro 785 retails for 7900.00 stock out of the box ski. The 2000SLX 1200 retails for 8100.00 . Thats a lot of money for 2 skis.

    then he said

    then use a 16-20 solas or skat on a 8-vain to get the best power..


    Is any of this true?lol I thought he was talking trash,,but also at the same time he could talk the talk too. but not getting complete prefessional answers either like keth or keddano or exlint. would give.

    you guys have never said sleeving was a good idea or boring is not the best route without heavey cylinder work, nor could you even get your hands on a pro in 97. you had to be sactioned as a racer with a sponser. as far as I know.. I bet a few pros slipped thru the cracks


    The Pro785 did win the world finals too. anyone have any old school info to add? I dont know all that much about the old days...97-2003 era. when the Pro785's were racing.

    then he says triple pipes only add 10HP to the ski.lol The best 10 iv'e ever seen.!


    Then the Bell went off. This guy has no clue, he's a talker.lol 10 horse... yeah right.


  2. #2
    Canadian Beaver Inspector jkindt's Avatar
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    The topic of your post almost made me want to avoid this one!!! I know you LOVE your pro, but really!!! I think that in order to stroke the crank, you also need to machine the crankcase to clear the rods on the downstroke.

  3. #3
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Anything is possible with money.But is it worth it? Yes you can put cast sleeves in them,and run 750 pistons. Hell,I think we threw in at least one 750 piston in towmans ski just to run it,or it was already in his box from someone before.

  4. #4
    1FASTXC's Avatar
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    I don't know a whole lot about the pro's specs since i've never had one, but i would think you could stroke the crank if you wanted. You would possibly need to sleeve the cylinders if the port timing is already right or on the high side to get it back to normal after stroking it, otherwise you could end up with too much port timing and make it a turd. The other reason to possibly sleeve it after stroking it would be to run a smaller piston to stay within a certain class's cc limit.

  5. #5
    bowsniper's Avatar
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    Those are great points.thx.. I know theres tons of people out there trying everything to see what mods can do.. not just people on here. lots of people probably dont even know this site exists. so I'm sure theres ways out there we havent seen to do different setups on cranks n strokes. just getting the right rods would be hard I would think. maybe some snowmobile rods huh..

  6. #6
    urugol's Avatar
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    I kinda asked the same question regarding my Pro rebuild, I got this response from Jay at sharpsmarine (he sounds like he really knows his shit).

    "We have a ductile iron sleeve that will allow you to run a standard 750 piston all the way up to a 1.00mm oversized 780 piston. This way you can use a cast piston such as Polaris or WSM. You could also run a Wiseco forged pistons as well. this sleeve is one that we came up with that is thick enough to allow the cylinder to be bored out this far.It keeps your cost down on the pistons as well as the down time if you have a engine failure. If you oversize your cylinder more than .010" from standard you will need to have your head re-chambered. Also if going larger that .040" you will need to have your port timing checked and or corrected. If we bore you cylinders(I know a long way from Australia) we check port timing for you each time the cylinder is bored and correct if need at no charge. Head machining is an additional fee. If you are running a aftermarket head we can re-chamber your head right off the bat for 1.0mm of oversize. we can also make sure you are safe to use 93 octane fuel."

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    The Fuji engines can be stroked to beyond 1000cc;

    My "new" Sharp's Marine 1010 Pro 785

  8. #8
    I'D RATHER SWEAT THAN SHIVER hyoctane23's Avatar
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    Quote Originally Posted by K447 View Post
    The Fuji engines can be stroked to beyond 1000cc;

    My "new" Sharp's Marine 1010 Pro 785
    I'm sure Jay and/or Art will chime in sometime, but from what I understand of the process, it isn't just as simple as increasing the stroke and that's it. Doing that changes the port timing amongst many other things. It isn't about a Polaris, but here is a little article about Yamaha stroker motors by Group K. Kind of an interesting read.

    http://groupk.com/tec-y-strokers.htm

  9. #9
    bowsniper's Avatar
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    Thanks, i read it.. its interesting they say that 4000 ft is the cut off. really 3500 ft.. and that at 7600 rpms? The pro does 7950rpms all day long. whats the speed of those pistons? 4500? how does it stay together?

    This just makes me wonder even more,, how does a motorcylce turn 14,000 on a bad ass bike without coming apart? were talking 8000 on a ski? whats the problems? the load? i just dont get it.. could ya put a harley davidson engine in a ski with a clemer belt set up? thats 80 cid. almost twice the Pro's 48 cid..?

    Just weird, bikes have super high rpms and skis cant or else they blow up. whats up with that?

    How about a ZX-14 kawisaki engine? 180mph plus on the street.

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by bowsniper View Post
    ...how does a motorcycle turn 14,000 on a bad ass bike without coming apart? were talking 8000 on a ski? whats the problems? the load? i just dont get it...
    Piston stroke on the high RPM engines is very short. Those engines are built for very high RPM power, but not much torque at lower RPM.

    Unlike any geared road machine, a PWC has one 'gear', and it is always engaged. A PWC engine needs to be able to twist that impeller up from idle without any clutch slipping or transmission gear ratios. That requires torque.

    Torque generally requires long piston stroke and cylinder displacement. Long piston stroke means limited top end RPM due to mechanical stress issues.

    Also, a 2-stroke ported for enough torque to get the RPM up under load will not be able to breathe properly beyond a certain peak RPM.

    The exhaust valves in your Pro 785 effectively have two exhaust port heights - one for lower RPM torque, another for better cylinder breathing at higher RPM.

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