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  1. #1

    Jet sizing HEELLPPPPPP

    Ok so i have a 2000 millenium GP1200r and i need help on jet sizing ... my current mods are
    D-plate with chip
    Riva race head 39.5 cc domes
    165psi comp.
    choke plate eliminated
    riva flame arresters
    riva free flow exhaust
    Riva C.D.I currently set on stage III
    9500 rpm P.V set to open at 6800rpm
    solas impeller with cone 12/22
    worx top loader intake grate

    so i would really appreciate any help i can get here thank you very much


  2. #2
    quadzilla's Avatar
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    Question eh.?

    Hey there boostonjuice..

    First of all welcome to the forum...

    Got to say you have some "unusual" settings going on there..??



    Quote Originally Posted by boostonjuice View Post
    Ok so i have a 2000 millenium GP1200r and i need help on jet sizing ... my current mods are
    D-plate with chip (good idea)
    Riva race head 39.5 cc domes (good idea)
    165psi comp. (seems a little high what compression tester are you using.?)
    choke plate eliminated (good idea)
    riva flame arresters (good idea)
    riva free flow exhaust (good idea if your compression is as high as you say.?)
    Riva C.D.I currently set on stage III (WHY..???)
    9500 rpm P.V set to open at 6800rpm (again WHY..??? this is a very high setting)
    solas impeller with cone 12/22 (Where did you get this pitch from..???)
    worx top loader intake grate (decent grate but not the best)

    so i would really appreciate any help i can get here thank you very much
    As for jetting i would think the tried and tested 110 low jet/ 125 high jet, a 1.5 needle and seat with a 95gram spring would put you very close..

    You really need to lower that rpm limit to about 7600 or so.. (there is NO reason whatsoever to spin that many RPM's..!)
    Also lower that power valve opening point..
    where did the prop come from..?? that pitch is bizarre..

    Do you have a tach and a GPS available..??
    How many rpm's have you achieved so far..??

    Post some more info if you can..

    We can move forward from there..

    Gerry

  3. #3
    Sorry wrong pitch i cant see what numbers im typing 13/19 solas prop.. and i havent taken the ski out yet with this setup and no im in Puerto rico so i cant really get to a digi tach that easy unless i order one from ebay or something but i do have a gps.. comp is 163-166-164.. and for the jet sizing you posted im scared to put that cause thats what everybody runs with the basic mods on stock compression wich i have a little higher comp. on mine and do not want to lean out..

    oh thank you for the welcome!!

  4. #4
    quadzilla's Avatar
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    Lightbulb ?

    OK then a 13-19 makes more sense..

    As for the jetting that IS what you want to run..

    Forgot to add disable the accelerator pump also..

    Start at 1 turn out on the lows and 1.5 on the highs.. (you will be close if not dead on)

    You really need to get your hands on a tach.. (you can't really tune a two stroke without one..!!!)

    Gerry

    EDIT:.
    Read this thread here:.http://www.greenhulk.net/forums/show...ave-used/page5
    Post 49 and 50 are relevant..
    There isn't likely to be anyone on this forum knows more about Yamaha carbs than Osidebill..!!
    Last edited by quadzilla; 09-08-2010 at 12:00 AM. Reason: more info

  5. #5
    Quadzilla Thanks for the help im going to get the jets tomorrow!! any idea on what kind of mph i should be getting?? all i need to do is beet my cousins sho!!!

  6. #6
    old school gp's Avatar
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    Quote Originally Posted by boostonjuice View Post
    Quadzilla Thanks for the help im going to get the jets tomorrow!! any idea on what kind of mph i should be getting?? all i need to do is beet my cousins sho!!!
    Is the sho all stock

  7. #7

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    I'm the furthest thing from a tuner/mechanic that you can imagine. It seems to me however that there are things that by themselves are no big thing, but in combination could be a problem.

    165 psig...... high heat in the 70% throttle range
    choke plates eliminated..... low signal potentially componded in the 70% throttle range
    aftermarket flame arrestors..... low signal in the 70% throttle range
    CDI at stage III..... potential advanced timing issues in the mid range (hot)
    PV's set to open at 6800...... I don't know what this will do temperature wise, but would bet that it would not help mid range accelleration

    With the right combination and in the right conditions, is there a potential for a mid range seizure?

    I would think 112.5 pilots would be the better choice to mitigate lean/heat issues in the mid range.
    Reset the power valves
    Set rev limiter to 7500 to minimize potentially twisting the snout off of the crank.

  8. #8
    Going to bring the rev's down.. but i really dont do to much cruising in the mid range maybe only 5-10 sec mid range most of the time its full throttle blasts and cruising maybe 1/4 throttle ... 1/4 throtle my ski used to cruise around 25 mph !!! the SHO does around 72 mph depending on conditions.. so im going to order to order jets tomorrow... So does everyone agree on 112.5 pilots 125 highs and 1.5 n/s 95 gram springs??

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