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  1. #1

    Join Date
    Jul 2013
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    Covington, LA
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    2007 RXT RPM drop

    New to the site. Been doing some research and cannot find anything that relates directly to my issue. Recently decided to get into skis. Purchased a 2007 RXT a few weeks ago.
    - green wheel
    - larger injectors
    - upgraded impeller
    - few other mods

    Bike was running 7700-7750 dead on 70MPH. Running it this past weekend RPM's dropped to 7550 still pulling 69-70MPH. Supercharger was rebuilt less than 20hrs ago this is when the green wheel was added.

    Any ideas what I should be looking for? Going to try and run it again one evening this week or this Saturday see if it was just a fluke.


  2. #2
    wotxxxsd's Avatar
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    May 2012
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    It's called heat soaked.
    When the temperature goes up EVERYBODY loses rpms & speed.

    When the waters are cooler & outside temps drop then rpms & speed go up.
    Rip on...

  3. #3

    Join Date
    Jul 2013
    Location
    Covington, LA
    Posts
    9
    Thanks for the response.

    Finally had a chance to take a ride this evening. Rained most of the day so the water was cool 82-84 degrees. Still getting the lower RPMS. Pulled her back in the shop, took off the SC intake. Wheel has a little slack in it. I can rock it back and forth, not much, but i can. Everything I read says the wheel should not move at all. This slack doesn't seem normal to me.

    Any ideas before I pull it and get it checked out. Planing on calling the mechanic the previous owner had do all the work early next week.

  4. #4

    Join Date
    Jul 2013
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    Covington, LA
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    also the wheel was greasy

  5. #5
    Mothman's Avatar
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    May 2011
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    West Texas
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    If it's humid (more than your usual conditions in LA), that'll eat rpm too.

    If you can spin the charger wheel around with your fingers, the slip needs adjusting.
    Greasy or oily? If the crank vent tube is still attached to your plastic intake tract, the charger wheel will be oily from pulling in oil mist. It's normal, unless it's really bad, then something else it up.
    Good luck!

  6. #6

    Join Date
    Jul 2013
    Location
    Covington, LA
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    9
    Cant spin it, the rock/slack in the wheel is normal? More oily than greasy. I have a catch can so shouldn't be spray. It wasn't horrible, enough to cover my fingers after playing with it.

    I'm leaning more and more to the weather just covering my bases. Thanks again for the help.

  7. #7
    Got Boost? psycho rxp's Avatar
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    where's your oil level on the stick? It should be in the middle of the 2 bends.

    top bend or above will cost u RPM's, and over oil the Intake tract...

  8. #8

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    Jul 2013
    Location
    Covington, LA
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    Dead in the middle.

  9. #9
    Got Boost? psycho rxp's Avatar
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    Check the nose cone on the prop, hasn't come loose, and slid up the driveshaft

  10. #10
    Quote Originally Posted by RXTLacombe View Post
    Purchased a 2007 RXT a few weeks ago.

    - upgraded impeller

    Bike was running 7700-7750 dead on 70MPH. Running it this past weekend RPM's dropped to 7550 still pulling 69-70MPH.
    Quote Originally Posted by wotxxxsd View Post
    It's called heat soaked.
    When the temperature goes up EVERYBODY loses rpms & speed.

    When the waters are cooler & outside temps drop then rpms & speed go up.
    Rip on...
    What's up Covington?! Old Metairie boy here

    Yes, everybody loses some RPM and speed in the heat (I lose only 150-200 in 110* temps), but this guy just bought this ski a few weeks ago...and in southern LA, his weather was no cooler in late June than it is now - hot and humid.

    Also, shouldn't his 215 motor be spinning the same 8100-8150 on that RXT as other 215 motors? (he basically implies it was running normal at 77-7750, which is very far from 8100 even if you factor in some hot weather).

    What impeller pitch do you have Lacombe? I know the ski is very new to you, but are there ANY other symptoms with the change in RPM? ANY vibration at idle and/or under throttle, change in pump or exhaust sound, etc? Does the RPM change come and go, or staying consistently lower?

    Are you reading the speed off your dash?.....they both only register a max of 70, so pretty much ignore that. RPMs always tell more/most of a story anyway.

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