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  1. #1
    Pwgsx's Avatar
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    951 Only Getting 5600 rpms

    Backstory: A buddy acquired a non working 98 GSX Limited that had a bad motor. He went with a rebuilt motor and is now running premix. Carbs were rebuilt using genuine kits and pop off was set right at 19-23 psi. He just got the engine broke in and changed the plugs. We checked compression and its perfect. He went to give it some WOT and he is only hitting 48 mph at about 5600 RPMS. On the trailer it will rev to 7000 no problem.


  2. #2
    SURFnTURF's Avatar
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    Sounds like either or both the raves are not opening or water lines are reversed into the pipe. Or rear water box controller isn't reducing water cooling at higher rpm. It should always flow but reduce at higher rpms

  3. #3
    Pwgsx's Avatar
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    Waterlines are verified correct. If I run with the Rave Caps removed I should get peak RPMs just crappy bottom end right? That would verify that the Rave solenoid is bad? The Raves came rebuilt with the motor so I know the bellows are good.
    Any easy way to test the water regulator?

  4. #4
    Tool Bag water worx's Avatar
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    Take the rave caps off & see what rpm it gets.

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  6. #5

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    The water regulator on the waterbox is known for having pinhole leaks in the diaphragm that render it essentially useless. You can remove the cap and look for water in the housing. Also you can remove the lines from it and unscrew the whole assembly from the waterbox and take it apart to look for holes. Also sand and dirt can plug the valve or the tiny orifice in the water box.

    What happens with the diaphragm is the small clamp that holds the lower part of it to the piston rubs a hole through it. If it has one tiny pinhole leak, you can carefully plug it with a tiny blob of black RTV to verify that performance improves, but the best route is to replace it with a new one. If this valve does not work, then the engine won't hit max RPMs.

  7. #6
    Pwgsx's Avatar
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    Hoping to check on Sunday!

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