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  1. #1

    Yamaha xl 1200 problem

    Hi everyone, i m new in here. I have problem, the rev limit on my engine is about 7000rpm and i manage to go 56mph at that rev range (7000rpm) my problem is that when i pull wide open throttle, the engine does not stay constantly at 7000rpm it goes down to 6000rpm and goes up again and stays doing so at middle to wide open throttle. It has nothing to do with the waves at sea and i can feel that when it drops rpm it lets off a little bit


  2. #2
    Any help pls??

  3. #3
    pokplalya22's Avatar
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    sounds like a powervalve issue. How do you know your rev limit is 7000? Do you have it set to 7000 with an aftermarket CDI?

  4. #4
    Because standard xl 1200 66v engine, they go upto 7000rpm in standard mode

  5. #5

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    Do you think that it is possible that you may not be getting the fuel that you need while riding at full throttle, and so that is why you are slowing down and loosing rpms? Have you tried chokeing it (slightly) while riding to get a little bit more fuel?

  6. #6
    I didn t try that, also should i try to rev the engine outside water? If the engine is running lean underload inthink it should be fine without load. Am i right??

  7. #7

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    A "load" is a relative thing, and yes you can run lean under a load, but just because you remove the load does not always mean you have stopped running lean.

    The question is do you have a fuel supply problem, a fuel delivery problem or a power valve problem. Making sure that the fuel supply from the tank to the carbs is one thing, making sure the carbs are operating properly is another. Then of course the valves are a seperate issue.

    What you have suggested so far makes me believe that you might have a fuel related problem, and the electronics that are controling the valves are telling the valves to close in order to make the most power that it can based on the (limited) fuel that is being used.

    For instance, when you reduce the throttle (slow down) and get below approximately 5000 rpm you are in fact reducing the fuel. The valves in response, begin to close to make the best use of the fuel being delivered. If your fuel is being reduced either by you reducing the throttle or some sort of restriction in your fuel line or problem with the carb internals of for what ever reason, the valves will begin to close in kind. In other words, you cannot expect the valves to open and stay open just because you pull the throttle. They open (and close) because you reached a certain rpm.



    Honestly, there is not enough info.

    Do some reading on fuel supply issues, carb issues (fuel delivery), and then power valve issues. You will start to see a pattern. In this way you will more fully understand and describe your symptoms.

  8. #8
    easiest thing to do is disocnnect the PV controller connector, pull off the rubber boot on the PV controller and manually open the PV's wide open. It will be sluggish off the line but see what your top end feels like. IF its consistent then you probably have a bad PV motor.

  9. #9
    YudLuz2's Avatar
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    The rev Limter is not 7000 rpms on a power valve motor. Sounds like you could have a lean issue or cat convertor falling apart inside your exhaust.

  10. #10
    pokplalya22's Avatar
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    Where did you get this info from? Also wtf is "standard mode"? Is there a magic button somewhere that Im missing?

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