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  1. #1

    Why the f**k is my GP1300R not breaking 70mph?!!

    I ran my ski today for the first time with my GPS to see where it stands. I am beyond disappointed. Currently I have an 05 GP1300R with the following mods.

    R&D Girdled heads, Riva free flow, TDR powerspray, R&D intake grate, Jims modded ride plate, Riva EFI controller, Riva Filter, Hot Shot Mod with Jetworks, Pump stuffers, PET Tach, Riva stainless wear ring, Solas 14/20 impeller, Cat delete, 85mm reduction nozzle, reinforced pump tunnel.

    I weigh approx. 215lbs, fuel tank was 1/2 full with Sunoco 93 and Klotz R50 mixed at 40:1, water was little choppy but ran passes when I found calm areas too.

    Top speed was 68.78mph. WTF?!!!


  2. #2
    powerstroke specialist mikegp's Avatar
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    well i just found the first problem , you weigh too much.

  3. #3
    powerstroke specialist mikegp's Avatar
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    Quote Originally Posted by nextlevelinnovations View Post
    I ran my ski today for the first time with my GPS to see where it stands. I am beyond disappointed. Currently I have an 05 GP1300R with the following mods.

    R&D Girdled heads, Riva free flow, TDR powerspray, R&D intake grate, Jims modded ride plate, Riva EFI controller, Riva Filter, Hot Shot Mod with Jetworks, Pump stuffers, PET Tach, Riva stainless wear ring, Solas 14/20 impeller, Cat delete, 85mm reduction nozzle, reinforced pump tunnel.

    I weigh approx. 215lbs, fuel tank was 1/2 full with Sunoco 93 and Klotz R50 mixed at 40:1, water was little choppy but ran passes when I found calm areas too.

    Top speed was 68.78mph. WTF?!!!
    now seriously,
    what are the compression #?


  4. #4
    Quote Originally Posted by mikegp View Post
    Quote Originally Posted by nextlevelinnovations View Post
    I ran my ski today for the first time with my GPS to see where it stands. I am beyond disappointed. Currently I have an 05 GP1300R with the following mods.

    R&D Girdled heads, Riva free flow, TDR powerspray, R&D intake grate, Jims modded ride plate, Riva EFI controller, Riva Filter, Hot Shot Mod with Jetworks, Pump stuffers, PET Tach, Riva stainless wear ring, Solas 14/20 impeller, Cat delete, 85mm reduction nozzle, reinforced pump tunnel.

    I weigh approx. 215lbs, fuel tank was 1/2 full with Sunoco 93 and Klotz R50 mixed at 40:1, water was little choppy but ran passes when I found calm areas too.

    Top speed was 68.78mph. WTF?!!!
    now seriously,
    what are the compression #?
    122 122 123

  5. #5
    powerstroke specialist mikegp's Avatar
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    way too low. they are actually lower than stock and to top it off 14/20 is too big for that comp.
    i see you have a pet tach , what were the rpms?
    another thing it caught my attention ,what kind R-d heads are those that it did not increase comp? where did you got that from ?

  6. #6
    Highlifeking's Avatar
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    Low compression for starters- get rid of the TDR water box for sure, and what were your RPMs?

  7. #7
    Duke's Avatar
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    Most importantly where does your pump shoe measure off your hull? Then whats the rpm? Then find your stock waterbox and get it back the hell back in there!!

  8. #8
    silver93t's Avatar
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    I would pitch down to a 13/20 and I agree about ditching the water box. A free flow is plently for these skis.

  9. #9
    Prism's Avatar
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    The first thing I would change is the R50 oil. This is not for use through injectors, or injection systems. It has a high castor content which is great for wide open very hot engine use, but scuffs at recreational/cooler temps. Klotz is awesome oil, and they have many varieties to suit a wide variety... for PWC their ski craft oil is great. Leave the R50 for the hill climb and sand/desert racing crowd. Don't take my word for it call them yourself and speak to a tech. Now then, as mentioned before...how recessed is the pump shoe in the hull? Needs to be a nickels thickness recessed all the way around. What is the ride plate height measurement? It should be between .950 and 1.10". For top speed its been my experience that around .980 ride plate height with .060 to .080 shims between the trim tabs and hull along with stepped sponsons works well. All skis will need tweaking for the max mph, but these are good starting numbers. For your setup with the 14/20 I would recommend an 87mm 5 degree exit nozzle to keep the RPM up. Make sure the nozzle and pump are shaved to allow the ride plate to sit at the proper angle. Also make sure the trim is centered in neutral. Make your speed runs also in neutral after adjustment. Check/try these and report results. What RPM do you turn now? Are you using an 800 or 1200 grate? Also, what are your EFI settings? Once all this is sorted we can continue with more.
    Last edited by Prism; 07-06-2014 at 02:21 AM.

  10. #10
    I was at 7120 RPM'S on the pet tach

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