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  1. #1
    Moderator OsideBill's Avatar
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    Old shool 99 GP 1200 questions

    I recently got a 99 GP 1200 it has the following upgrades

    Protec high compression head w\girdle
    R&R jetech reed spacer
    reeds brand unknown at this time
    Stuffers not sure of brand
    protec modified CDI
    TDR water box with sprayer (but it is not used)
    R&D power plenum w protech adapters
    Jetworks valve to stinger
    primer
    modified oem carbs not sure of pop off or jetting yet
    dual fuel feed
    Riva Sponsons
    runs on approx 96 octane 4:1 mix of 91 and 110 with 50:1 amsoil dominator
    Umi steering (Thanks Flying Scotsman) with renthal bars, riva drop nozzle kit and ODI grips, stock finger throttle
    under the water it has a worx grate , R&D ride plate with 1/16" shims in the front and 3/16" shims in the rear and a new solas XO impeller.

    I took the ski out first time last week it fires up on the first try every time I am assuming this is due to compression. the tdr makes it loud and it idles like a big block jet boat, seems like it loads up a bit. it is very quick out of the hole it will pull air if you do not drop the nozzle. it will get up over 60 (61.2 GPS best) and flatten out. rpms peak about 7000 on the stock meter water temp was mid 60's on a fairly dry day in air in the mid 80's
    I will be pulling the intake out for inspection and sending the carbs in for service and checkout they look like the venturi has been bored a little on the id it does not have the cast appearance my other carbs have. I am looking to get top speed from a single pipe. I have an 1100 stinger available and was told I could gain from this I am looking for suggestions from the forum and options this is my migration ski next year I will move up to something more powerful. I am a competent mechanic and excellent fabricator I am new to the two stroke world so please Jump in and send me on my way. I have read Mike Thornes page at extreme racing and find it covers hull mods but is lacking on the rest I am still looking for the "more to come" no offense intended Mike. I have also read Group K's info. So Please jump in and help.

    Regards, OsideBill


  2. #2
    Flying Scotsman's Avatar
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    Hey bill id loose the tdr I hear it does nothing for rpm.
    If you run the 1100 stinger up the octane some more.
    Stingercreates more heat so compensate with fuel.
    How high is your compression now.
    You need a tach to dial in your prop.
    I think a 13/19 solas or 14/20 tweaked to your rpm goal.
    Shim the plate in front not the rear.
    J-ME was running high compression and I think a 1100 stinger he is always helpfull he can help you.
    SCOTT.........

  3. #3
    spud's Avatar
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    I've got the complete 1100 stinger all put together I'll sell you for $25 if your looking. I also have a new pump with bearings installed I'll sell for $50 if you are looking for an extra.

    other things laying around 0° nozzle stock impeller a bunch of junk.

    I'm in Oceanside also. Just sold my GP1200 and started a new project.

    I was getting 63 consistently out my GP1200

  4. #4
    GPRPITMAN's Avatar
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    I have an xo prop for that ski which is the one you want to go with, in great shape

  5. #5
    Mongoose's Avatar
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    If you ever need a Riva quick rev digital cdi unit with adjustable curves and rpm selector, drop me a line. I'll leave it go cheap (Well cheapish! )

  6. #6
    ....back from the dead.... J-ME's Avatar
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    If the stinger is orginal equipment from the the 'ski it will already have the 1100 insert in it. (99 only)

    R&D or ProTec with the wings cut off are the grate of choice on the GP.

    If it is ported (and it sounds like it is) the J prop will give you the highest top speed.

    I agree with Scott, get rid of the TDR waterbox and make sure the external exhaust flap is removed.

    The Riva CDI will help you out as well.(with a better advance curve) The ProTec one only removes or raises the rev limiter.

    Post more info as you find out about it.

  7. #7

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    If you decide to go with a Solas "J",I have one for sale.

  8. #8
    Moderator OsideBill's Avatar
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    Thanks for the replys I will pull the intake this weekend so I will have more information next week on specs. I do have the stock waterbox and will install it, I will it put the TDR on ebay. I have a brand new XO in it and I also have a modified XI I got from Karl Payne, I have not tried it yet. I have read about the "J" and am interested in trying one can't have too many props. I have been looking into the Riva and R&D grates I am attaching photos it looks like Riva has no wings on it if so I would choose this please let me know your thoughts. Spud pm me your number and I will give you a call regarding the parts I have a complete 1100 exhaust already sounds like I won't need it. I am interested in the pump and nozzle. let me know on the grates I will order this this week.
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  9. #9
    Moderator OsideBill's Avatar
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    pump shoe?

    anybody ever have or use one of these? I got this with my ski the guy told me you could run regular style yamaha and aftermarket grates with it. I was going to put this on ebay I do not know what grates would be compatible so it is difficult to list. Thanks Bill
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  10. #10
    ....back from the dead.... J-ME's Avatar
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    I would choose the R&D over the Riva grate. Sorry Riva
    Never saw one of those "grate adapters" before.
    Post a couple of pics of your 'ski for us old school guys

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