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  1. #1

    XL1200 LTD RPM Dropping at WOT

    Having finally solved my bogging issues with the xl1200 and also serious cavitation. see post here

    I now have a problem where the rpm drops suddenly at WOT to approx 6K. The engine sounds as if it is labouring. This does not happen all the time. If I let the ski return to idle and floor it, goes to 7K. Compression is perfect.
    Tank check valve is working correctly.
    Carbs have just been rebuilt
    I did notice a tiny drop of water in the fuel filter, very little though.
    Tank flap has been removed
    what might be causing this problem.

  2. #2
    eb87's Avatar
    Join Date
    May 2010
    South East Coast
    Sounds like fuel starvation, have you checked the vacuum hoses going from the case to the carburetors?

  3. #3
    Pulse lines are fine. Anyone have any other ideas.

    It developed the same problem again, revs dropping suddenly to 6k (one thing I did notice (or imagine) is that is only seems to drop the revs in choppy water. On smooth water it seems to run to max rpm, however the speed seems to be down 20km according to the stock spedo.

    Anyway I remove the engine again and did a leak test. Found the PTO seal leaking badly so I replaced all 3 seals, engine back together and did another leak test. Tested it at approx 10psi for over 2 hours and the pressure did not drop. So all is perfect there.
    Back to the water again today and all seemed fine for 10 mins or so and then I hit some choppy water and the revs dropped to 6k and remained there.

    Anyone have any ideas as to what the hell is happening here.
    So far I have done the following.

    Rebuilt carbs, leak tested them and checked pop-off
    New crank seals and leak tested engine
    Removed flap in tank
    Bypassed the fuel selector
    Checked all pulse lines.
    Check tank check valve
    New fuel filter
    Pressure tested fuel tank and lines.

    Only thing I did not do was adjust the high speed screws when rebuilding the carbs as I assumed they were correct.
    Another point to note is that the speed is topping out at 80-85 km which seems very low to me.

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