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  1. #1
    mr. happyfunbear tenjuna's Avatar
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    Chicken and Egg Question

    I am reviewing my sl650 rebuild project and a question just occurred to me...if you have to break-in the engine AND tune the carbs, which do you do first? obviously you can't do both at the same time.

    I know the rings need to be seated, but you can't really do it correctly unless fuel delivery is right. but if you worry about tuning carbs you aren't going to be able to seat the rings properly right away.

    does it matter?


  2. #2
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    If you start with your tuning,like you did at Starved Rock, you will be seating the rings and also going thru the heating and cooling cycles which is really the first thing to do for your pistons. Do a pass, stop and check plugs and adjust,allow engine to coll some and repeat. The Rings seat from time running. Doesn't have to be non stop running.

  3. #3
    mr. happyfunbear tenjuna's Avatar
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    ok that makes sense, tuning the carbs like I did at Utica was exactly what I was going to repeat once the engine is running.

    thanks!

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    There was no Q about any chicken or eggs.

    WTF??????






    Rings being seated are priority.

    You need to add more oil to the gas during break in. So adjusting the carbs to that mixture will throw you off a bit.

    You'll also never get to WOT until your rings are seated if break in is done properly.

    Therefore, carbs can't be dialed in until the rings are seated.

    Get them close, get the rings seated, then adjust away my friend.

    Good luck.

  5. #5
    Tony's Avatar
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    BTW, the egg came first.

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Tony View Post
    BTW, the egg came first.
    But of course

  7. #7
    mr. happyfunbear tenjuna's Avatar
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    Quote Originally Posted by Tony View Post
    BTW, the egg came first.
    actually the correct answer is the chicken was a mutation of another species...so while it came from an egg, it wasn't a chicken egg.

    so technically, chicken came first.



    aaaanyway, I hear you xlint, so I will set carbs to factory plus 1/2 turn, break in the engine, then go back and do a tuning cycle.

    ugh, that's going to take me an entire weekend.

  8. #8
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    The little extra oil your running during break in shouldn't throw the carbs off a whole lot.(besides you have to tune for the first tank of running with the oil in it.) (remember with that 650 you can run all day long and still not be out of fuel) But you don't want to burn down while trying to get some hours on it.

    And you would want to dial it in again after you run your break in fuel out,and refill without the added oil.(if your running oil injection.)

    The rings seat by wearing into the bore(crosshatching),which can only be done thru running. Maybe 2 hours,maybe 10,I don't think anyone can give a definitive #.About the only why of knowing would be to check compression after you do your riding,and when it stops climbing,your there.

    So my priority would still be on getting the ski real close,then get some hours on it carefully during the first full tank.

    I think me and Kevin are really getting at the same thing.

  9. #9
    mr. happyfunbear tenjuna's Avatar
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    sounds like I am going to tune the carbs twice.


  10. #10
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Yes, but the second time will just be slight. Or you may not find it doesn't need changing at all.

    Racers will tune on the day of the race for the conditions of the day and location, but they are looking for every bit of edge.

    Think about running in early summer with 60* water and 75* day VS mid summer with 85* water and 95* day. The tuning should be different,b ut will it affect the ski that much......not really.

    They do not adjust the carbs from the factory to break in conditions and then tell you to readjust afterwards.

    A friend just bought a brand new 09 Ski Doo Sled, In the manual (and dealer) says to add a 50:1 oil mix to the gas for the first tank for break-in..... Nothing about readjusting carbs afterwards.

    Alot of times on here we are all looking for every bit of performance out of our modded skis. But many on here are just rec riding. Some times we make too big a deal out of small things that really don't mean crap to most.
    Tune it a little rich and have fun and let it live.

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