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  1. #1

    GP1200R- Reinstalling powervalves- Which direction do they face??

    I'm just now reassembling my gp1200r motor that I took out of the ski last fall and rebuilt over the winter. As I'm dropping the powervalves back in I can't recall which side of the valve faced the piston. The service manual appears to show the flat face towards the piston and the concave side facing out toward the exhaust manifold.. Is this correct?? Any help would be greatly appreciated. Thanks


  2. #2

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    There is a notch or groove on one side of the power valve, it faces down toward the crank... accord to what you are asking the power valve only goes in 1 way. the concave goes toward the piston and the flat face with the stem with the bushing goes toward the cover of the power valve... Make sure the groove faces down toward the crank.

  3. #3
    No, lol, I wasn't trying to put it in upside down... I was referring to the orientation of the valve from front to back, not top to bottom. On the bottom edge of the valve, the part which actually protrudes into the exhaust port, the entire lower edge is cut in a slight "U" shape, but on one side it is flat and the other side it is beveled/concave on the face of the valve from the bottom edge going about an inch up. With the valve installed completely, which side should be facing the piston and which side exhaust?? Anyone know what I'm talking about, it's kind of hard to describe.. I'll try to find a pic..

    Quote Originally Posted by Speed796 View Post
    There is a notch or groove on one side of the power valve, it faces down toward the crank... accord to what you are asking the power valve only goes in 1 way. the concave goes toward the piston and the flat face with the stem with the bushing goes toward the cover of the power valve... Make sure the groove faces down toward the crank.

  4. #4
    mudslanger's Avatar
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    OK put your power valve in the cylinder and look through the exhaust port then if you pull the power valve out a little bit it should be the same angle as the top of the exhaust port. in other words it will make the exhaust port a straight tube when the power valve is open. but when the power valve is closed the tube will be restricted or smaller.

  5. #5


    Here is a pic of the beveled side..


    Both ways it opens and closes the port opening, I'm just concerned because it has a bevel/relief cut on one side of the bottom edge and I'm not sure if it's for piston clearance if facing the piston or if it's for the exhaust to flow characteristics if facing outward toward the exhaust..

  6. #6


    and here is the flat side, the face of the valve is larger on this side... (this broken valve is not mine...)

  7. #7
    Either way seems to fit ok, and common sense tells me to face the beveled side towards the piston, but if you look in the service manual it really looks like they show the flat side facing the piston and the beveled side towards the exhaust manifold. I'm confused on which way to install it and don't want to destroy my fresh motor over a stupid mistake. Anybody have a picture of the exhaust port of their cylinder with the valve closed??

  8. #8

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    Quote Originally Posted by Speed796 View Post
    There is a notch or groove on one side of the power valve, it faces down toward the crank... accord to what you are asking the power valve only goes in 1 way. the concave goes toward the piston and the flat face with the stem with the bushing goes toward the cover of the power valve... Make sure the groove faces down toward the crank.
    1300 power valves have these groves 1200 power valves don't have them.

  9. #9
    mudslanger's Avatar
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    The beveled side goes to the exhaust port. and the flat part to the cylinder.

  10. #10
    Quote Originally Posted by mudslanger View Post
    The beveled side goes to the exhaust port. and the flat part to the cylinder.
    Alright, thank you. That's how I installed them yesterday, seemed to match the port best.. It eases my mind to know I have them in correctly before I fire up my fresh motor today.. I have too much work into it to smash my pistons into my powervalves or have something catostrophic happen on startup, lol. Thanks again for you help!

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