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  1. #1
    JFizzleJR's Avatar
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    Reverse Bucket & Bolt Holes

    I had a stock best of 68.1 mph with 67.9 & 67.8 runs to verify on my 05 RXP. i usually got about 67.4-67.6 though. conditions were glass or close to it during all the runs. air was 75° and water was 70° @ 8000-8050 rpms. rider weight is 150lbs and rode in the superman position. 67.9 was with a full tank of gas, 68.1 was 5 bars, and 67.8 was 2 bars.
    i filled the grate holes and rideplate holes, trimmed the lip off the reverse bucket, but i did not make the rideplate match the grate surface. i did 2 test runs with the same conditions and got 68.2 @ 7950 rpms w/ 2 bars of fuel and then 68.6 @ 8050 rpms. so i gained about .5-1mph after both of those mods. trim was all the way up after the ski planed out and these are the only mods done to the ski, everything else is stock.
    my concern is the porpoising and i was also hoping for a 1.5mph gain. the water was nearly glass and i had to take 5 runs before i could get the ski to stay in the water completely. it didn't porpoise like that before i filled the holes and cut the reverse bucket. did anybody else experience porpoising from these mods? and if so what did you do to stop it? also is the .5-1mph gain accurate or did i go wrong somewhere?


  2. #2
    ramnj's Avatar
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    Do you have block-offs on your ski?

  3. #3
    JFizzleJR's Avatar
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    Quote Originally Posted by ramnj
    Do you have block-offs on your ski?
    no but there was no porpoising on the same conditions at full throttle before the reverse bucket was trimmed and the holes were filled..

  4. #4
    Site Admin Green Hulk's Avatar
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    Having the trim all the way up is not the best position for top speed. Try 1-2 clicks above midrange.

    Trimming all the way up will also increase porpoising.

  5. #5
    JFizzleJR's Avatar
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    1-2 above midrange i didnt know

    even if i had it trimmed all the way up, can there be anything i did that would add porpoising when there wasnt any before at full trim??

    and do you think making the rideplate flush with the grate would give me the rest of the speed i was looking for? (.5-1mph more).

  6. #6
    Got Boost? psycho rxp's Avatar
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    Trim is definately too high, and will cause porpoising. Like jerry said lower it to just above neutral, and you should see even more speed. If u still have the opas in place Buy the RE block offs in jerry's store (they are the best.) and no more porpoising, even with no fuel ,and full superman!

  7. #7
    JFizzleJR's Avatar
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    Quote Originally Posted by psycho rxp
    Trim is definately too high, and will cause porpoising. Like jerry said lower it to just above neutral, and you should see even more speed.
    ..i now understand that the trim was too high for trying to get a max speed, but shouldnt the difference between stock speed and the after-mod speed be the same when compared as long as all tests were at full trim?
    for example i'll create a hypothetical situation.
    68.0 mph stock trim all the way down ......... then filled the holes cut the reverse lip off then went out on the same conditions
    68.5 mph trim all the way down..
    isn't it safe to say if:
    ideal trim position stock would've been: 68.5
    ideal trim position after modifying would've been: 69.0???

    summary of what im getting at:
    1) even if i did not find my real top speed bone stock b/c the trim was in the wrong position, shouldn't the .5 mph increase be persistant when comparing speed runs done at the same trim position. (comparing before and after the mods)
    2) will matching the grate surface and rideplate give me the 1-1.5mph increase people are seeing? or will the .5 mph increase remain?
    3) the porpoising did not occur at full trim on my testing conditions until i filled the holes and did the reverse bucket mod. what could be causing the sudden change? <--- this is the information i am trying to verify..

    also, in everyone's opinion is it better to buy $300 opas blockoffs to stop porpoising or make a $5 block-off plate when looking from the viewpoint of a recreational rider. don't get me wrong, i love to go fast, but i'm not trying to build a race ski, i'm just trying to take steps towards a ski that is a few mph better than stock and i'm trying to reduce the porpoising.

  8. #8

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    I bet the proposing came in the difference of fuel levels.

    T

  9. #9
    JFizzleJR's Avatar
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    Quote Originally Posted by TLR
    I bet the proposing came in the difference of fuel levels.

    T
    my problem with believing that is i had no porpoising with 2 bars at 67.8 mph with trim all the way up. now i have porpoising with 2 bars at 68.6 after the reverse and bolt hole mods while trim was still all the way up.

    another thing i can't explain is how i didn't gain much speed after i went through an entire tank. i got 67.9 full 68.1 5 bars then i got 67.8 with 2 bars and 67.6 after the low fuel warning. i seemed to be going down in speed while gas was depleting.. i guess that could also be related to trim position. i can sort of see why a speed gain didn't occur while fuel went down but i can't see why the amount of porpoising increased after filling the rideplate holes and doing the reverse bucket mod.

  10. #10
    You can rule out those 2 mods from causing the porpoising, I understand what your saying, if you don`t have a wedge instalkled in your ski, then the bucket mod was unneccesary, it isn`t doing squat for ya!...PR...

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