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  1. #1
    snowrunner's Avatar
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    XLT Top Speed Issue - too many RPM's????

    Fianlly had a great weekend to see what the old XL1200l (XLT) could do in good conditions.

    With all the mods listed below I was able to hit a new high of 63.2. My Tiny tach peak RPM was ~7200 on a 75 degree day. I was on 1/4 tank of fuel, 11/18 IR (14/20 hub) Prop. Beat two Honda 12F's (turbo two seaters whatever they're called).

    However, I don't think this is everything it can give. I'm wondering if I'm bouncing off the rev limiter or falling off the power curve. My rev's seem too high (in a prior post I ran extra oil in the fuel and could only muster 7100 RPM). I ran within .5 MPH of my peak speed with 2/3-3/4 tank of fuel when racing the Honda's. Before I would gain 2-3 MPH on a light load of fuel (low fuel alarm on). I was hoping for 64-65.

    I ran a 62.5 on a box stock R&D plate and solas 12/18. Went to the I full Mod plate and 11/18 IR prop and only gained .7 MPH?

    I haven't filled the holes, as I don't really know what to use? How hard is the stuff to remove to get at the bolts if needed?

    What is the best prop? Tweaking mine to a 12/19 or getting a box stock solas 13/19? Something else?

    Any help would be appreciated. I'll be calling Carl in the morning too.

    Would like to do something this week.

    Thanks!
    Last edited by snowrunner; 07-23-2007 at 11:42 AM. Reason: new title


  2. #2
    snowrunner's Avatar
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    IR

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    Last edited by snowrunner; 07-24-2007 at 09:33 PM.

  3. #3
    need4pwr's Avatar
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    You could still tweak that prop and get some more speed. What was the humidity (if any)? wind? All those have a factor also.

  4. #4
    dhoad's Avatar
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    call carl and talk to him about shimming the plate. his plate made big difference on my xlt
    Last edited by dhoad; 07-24-2007 at 12:36 PM. Reason: spelling

  5. #5
    Moderator RX951's Avatar
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    Carl, Jims 1300, where y'all at ? you know these XLL / XLT threads need attention !

  6. #6
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
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    With an out of the box 12/18 and a modded plate you should be at 65 to 66 mph. I would call Carl and see if you did something different in setting up his plate.
    Last edited by JIM'S PERFORMANCE; 07-23-2007 at 12:37 PM.

  7. #7
    snowrunner's Avatar
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    JIm,

    One of the guys on the forum threw in a modded 11/18 from a 14/20 - going off the norm there.

    I weight 215. Real light wind if any. Humidity was ~80%.

    Plate is shimmed.
    Last edited by snowrunner; 07-23-2007 at 07:37 PM.

  8. #8
    moving???

    snow, a 14/20 concord depitched to 11/18 is still a relatively STEEP impeller and it takes a LOT of umph to pull it. Its still conciderably steeper than a 13/19 impeller. I would look there first. if its too steep for your application, the speed gain ( if any ) would be minimal or even slower.
    I dont know which version of rideplate you have since you bought it used. but even the earliest versions ( when shimmed correctly ) yielded substantial gain.
    We had xll's back in 00-01 with level 2's and those depitched 14/20's ( and the early modded plates) running in the 69's same boat equipped with 13/19's would run high 66's to 67's

  9. #9
    snowrunner's Avatar
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    Carl,

    Here are the pics of the plate. Can you tell from this?

    My tach reading, if accurate (tiny tach commercial), would indicate below 7100 if the prop was too tal - wouldn't it? I'mm pulling these RPM and MPH with nearly 3/4 tank of fuel. When I lighten the load of fuel, shouldn't I be picking up a few MPH or is the rev limiter cutting me down?

    Didn't your phone message say you're in the process of moving?
    Last edited by snowrunner; 08-03-2009 at 06:49 AM.

  10. #10
    snow, looks like a very early mod how many shims under front bosses ( toward front of ski ) should be 0 under rear bosses.

    On the XLL from a completely full tank to an empty tank is EXACTLY 3 radar proven MPH. theres almost 1mph from when your low gas buzzer starts going off to empty-- we tried this and made almost 15 more radar passes "on the buzzer"

    go back and narrow it down-- doing 2 mods at once you cannot tell whats doing what.
    the rpm's sound good though

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