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  1. #1

    Join Date
    Aug 2009

    GP1300R staying at 3000rpm

    Hello to all of you,

    First a little introduction as I'm new on this forum...Please don't pay too much attention to my english as I'm French...nobody is perfect!

    I usually go a lot on french forum but I've a question that couldn't found an answer on these forums...One of the guys told me to have a look here and I saw quite a lot of interesting conversation, so you might here from me now!

    I'm the owner of a GP1300R, year 2003. This last month, I had a bad issue with it as the crankshaft broke at the flywheel area. So I removed the engine and changed the following parts:
    -crankshaft (hotrod)
    -complete pistons and gasket kit (wsm platinum kit)
    -stator and ignition sensors.
    -hull bearing assy.
    -shock absorber (motor's supports)
    -cam link between the exaust valves that were worm
    I did complete cleaning and inspection of the valves, removed the oil pump to use pre-mixed full...And the result is great! This ski is now a rocket, even better than before...
    It was already running with D'plate, extended bottom riva plate, drop nozzle and a few things but the acceleration is really better now .
    I've the workshop manual and did everything in accordance to it, so I think mecanically, this ski is OK.

    Now, you know better the history of this machine (and me), I can come to my question:
    Since the ski was back on the water, I spent a lot of time checking it, making sure everything runs smoothly...and of course find something that looks strange for me but might have been already here for a a long time.

    If you do a straight line with full open throttle for a few seconds, if you release suddenly the throttle, the engine will stabalize for about 2 seconds at 3000rpm and then will go back to normal slow motion.

    On this GPR, you might know that there is a "learner system". Meaning, if you release the throttle and try to turn handle bar, a sensor will see that and a stepper motor will hit the throttle for you, helping you to avoid collision.

    On this machine, I had it knew, and this thing as never really work. So when I saw this problem, I thought it could a problem with that safety. So I unplugged the sensor of the handle bar so the ECM will not see it anymore. The problem was cured immediatly, meaning the release of the throttle was giving immediate slow motion, even after a long ride at full throttle. Only an error message comes on the instrument panel...and I would like to get this away and cure correctly the problem.

    I had some discuss with many peoples here and I was advised to replace the stepper motor on the injection system. This part is not available at Yamaha (so of course they tried to sell me the complete injection system), but I was lucky to find a used one on the net and replaced it.

    But the problem is still the same. So now I can see only the following options:
    - the stepper motor I had is bad too...
    - This reaction of the machine is normal (I saw that somebody mentioned that in your forum), but then I would love to understand why, and honeslty it's really dangerous as the machine is really slowing down with 2 seconds delay.
    - the sensor detecting the position of the handle bar is damaged
    - The switch detecting the position of the throttle is damaged
    - the ECM unit is dead...

    So I would like to knowif some of you have allready experimented this trouble. As you are many riders of this GPR I would like also to know if some of you could do that testing for me: ride with full open throttle a few seconds and release it and check if the RPMs go down immediatly or step at 3000RPM for 2 seconds before. If all your GPR are doing the same...then I'll have a think it is normal...
    If some of you have any idea of what is involved with this, then I'm ready for advises

    Thanks in advance for all your help

  2. #2
    quadzilla's Avatar
    Join Date
    Apr 2007
    LOCH NESS Monster-Land


    Hey there Fullgaz...

    This thread should go some way to helping you out...


    Oh., and welcome to the forum...


  3. #3
    WATER WOODY's Avatar
    Join Date
    Aug 2005
    Minden, Nevada, United States
    Welcome to GH. First question is: Did you pressure test the motor???

  4. #4
    Moderator RX951's Avatar
    Join Date
    Apr 2005
    League City, Texas
    welcome to the forum

  5. #5

    Join Date
    Aug 2009
    Thanks to all of you for your welcome!

    It's amazing to see the amount of modified GPR's you have on your site...In france it is not so comon...

    Back to this problem, it is funny to see that Yamaha finally modified the sensor assy, thanks for the link!

    I've also tried to dismount the sensor, tape it inside the hull but no way, as soon as it is plugged, the RPM stay at 3000 for 2 seconds when I release the throttle after a full speed...

    But do I'm the only one to have feel this strange 3000rpm step?
    Does somebody know how to override the stearing sensor?

    Just for fun, here are a few videos that I let on Youtube with my friends...As you will see ours lakes are very narrow compare to yours but we still have fun like childs...

    Have fun!


  6. #6

    Join Date
    Aug 2009
    Oh...I forgot...

    What do you mean by pressure test the motor? Do you speak about the engine of the ski or the stepper motor that pushes on the throttle?

    If you suspect the engine, as it is running perfectly when I unplug the steering sensor I really think it is ok. Then do you have a test I could use for the stepper motor?

    Thanks again...

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