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  1. #1
    Canadian Beaver Inspector jkindt's Avatar
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    Holeshot Performance

    What upgrades are generally considered 'holeshot' upgrades?
    What can be done to my SL650 to improve its launch?
    High compression heads? Porting? Polishing? Lightweight flywheel? Nitrous Oxide? Bigger jugs and pistons? I had thought about using 780 jugs with +1.5mm pistons and a 785 crank with shorter rods but that, I think is just a dream. Would prefer to run it for a season first before making such major internal changes. I may be getting a 785 case for this engine anyways. What do you think? What would be your mods for this ski?
    Last edited by jkindt; 10-19-2009 at 10:08 PM. Reason: missed some info...


  2. #2
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    In holeshot are you talking the take off acceleration?

  3. #3
    Canadian Beaver Inspector jkindt's Avatar
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    Yup! The launch! Gettin' out of the hole!

  4. #4
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    By the time you dump money and time to make it bigger and better,you'd be farther ahead to buy a ski with a bigger motor.You could change the jugs,pistons and heads,as the case,crank and rods are the same on the 650,750,and 780's.
    What year 650?

    Adding a ATT to the pump would help holeshot,Also there are some aftermarket props that might also help. Normally you trade speed for holeshot.

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    By far the most cost effective acceleration upgrade for a 650 is to sell it and buy a bigger engined model. Really.

    If you like the compact size of the SL hulls, the Pro 785 model offers blistering acceleration and tight handling. It is technically a little more complex to maintain, but those who have them, love them.

    Otherwise, look for a 1050 or 1200 engined Polaris SLX. Very fast, with strong engines. Easy to maintain, and quite reliable overall.

    There is a Pro 1200 version, which offers much of the cornering power of the Pro hull with the simplicity of the 1200 engine. If you want even more power, you can add triple tuned pipes to the 1200 motor - and hang on!

    Look here for more info on the various Polaris models;
    Polaris PWC related information



  6. #6
    mr. happyfunbear tenjuna's Avatar
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    Quote Originally Posted by K447 View Post
    By far the most cost effective acceleration upgrade for a 650 is to sell it and buy a bigger engined model. Really.

    If you like the compact size of the SL hulls, the Pro 785 model offers blistering acceleration and tight handling. It is technically a little more complex to maintain, but those who have them, love them.

    Otherwise, look for a 1050 or 1200 engined Polaris SLX. Very fast, with strong engines. Easy to maintain, and quite reliable overall.

    There is a Pro 1200 version, which offers much of the cornering power of the Pro hull with the simplicity of the 1200 engine. If you want even more power, you can add triple tuned pipes to the 1200 motor - and hang on!

    Look here for more info on the various Polaris models;
    Polaris PWC related information

    +1

    in my opinion, the logical upgrade from a 650 is an sltx 1050...they don't cost much more, maintaining them is more or less the same skillset, and you would be getting a ~50% performance boost simply by sitting in a different ski.

    get the 650 running solid, sell it for $850-1000, spend ~$1500 on an sltx 1050, you will be much much happier and it will be a lot cheaper than chasing the dragon on a 650.

    as k447 said, if you like the sl hull (wouldn't blame you I love it) then get a 785 pro if you can find one.

    obviously if money is not an issue for you do what you want, but I am only rebuilding my 650 and I have spent more money than I originally paid for it. I am ok with it since I am learning how to rebuild engines in the process, but otherwise it simply would not have been worth putting a lot of money into.

  7. #7
    Canadian Beaver Inspector jkindt's Avatar
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    Okay, maybe I sounded a bit over anxious. I understand that it is not really $$ smart to spend a ton trying to make the smallest motor make the most power. I just want to optimize what I have and possibly upgrade it to a 750 or 780 in the future and don't want to invest in any upgrades that will have to be changed out if and when this happens. Like I said, I want to run it with stock std. bore 650 for a season. This will end up being the wife's ski and I know if we make it launch good and solid that she will be more than happy with it. For myself, I would like nothing better than to find a Pro 785 to play with, but there's not too many of those in the middle of the prairies in Canada.

  8. #8
    mr. happyfunbear tenjuna's Avatar
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    it sounds like you are doing what I did: keeping the 650 for the wife and buying another ski for you...in that case just fyi the "upgrades" for the 650 I decided on for bang-for-the-buck (this is beyond the maintenance parts and the engine rebuild I am in the process of doing):

    variable oil pump ($20 from a GH member, $12 for the carb lever at bikebandit.com)
    reed spacers ($20 from a GH member, $47 for the longer bolts and studs at bikebandit.com)
    aftermarket reeds (boyesen power reeds for me @ $112 at ebay, they get more expensive from there)
    extended jet pump with 12/17 solas swirl impeller and 780slx extended ride plate (ride plate is up to $75 used on ebay, impeller is about $120 new, pump is $125-$350 on ebay depending on what you get)

    expected cost all said and done: ~$500, more or less. you will likely gain 10% top end and a definite punch in holeshot and acceleration, but in the end it is still a 650. this is more or less like adding a turbo to a yugo. sure it will be faster, but it's still a yugo.

    the oil pump will greatly reduce oil consumption. reed spacers and reeds will give you some oompf. the jet pump/impeller/ride plate is the moneymaker upgrade for this ski. better handling and top end.

    beyond that, you could tinker with painting and truing the hull, replacing worn/faded parts, etc...I wouldn't go too far though unless you are keeping the ski for 10 years...you will never get your money back for it.

  9. #9
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    [quote=tenjuna;1244026 if you like the sl hull (wouldn't blame you I love it) then get a 785 pro if you can find one.

    [/quote]This is not true. The SL and PRO hulls are 2 TOTALLY different animals.

    The SL is more flat bottomed, while the PRO is a deeper V. The PRO will carve a hard turn while the SL will wash out.

  10. #10
    mr. happyfunbear tenjuna's Avatar
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    Quote Originally Posted by xlint89 View Post
    This is not true. The SL and PRO hulls are 2 TOTALLY different animals.

    The SL is more flat bottomed, while the PRO is a deeper V. The PRO will carve a hard turn while the SL will wash out.
    I stand corrected, I thought the only difference in the hull was the sponsons.

    oops sorry.

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