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back-cut on stock valves?

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    back-cut on stock valves?

    Hi all.

    The potential project this winter is to install 1150 cams in the 1100 es. I need new valve stem seals, and since I have the cams I figure "as long as I'm in there...."

    I have a few questions, One is...

    A valve job has been recommended to me, radius cut and back-cutting the valves. I have heard that suzuki recommends AGAINST lapping the valves, due to a loss of surface hardness. How does this warning apply to back-cutting the stock valves?

    I am trying to keep this little project from getting too out of control....Its too easy to add things to the list...head work. big bore. etc etc.

    Thanks for any insight!

    Greg
    1983 GS 1100 ESD :D

    #2
    The area of the valve which receives the back-cut does not come in contact with the valve seat area, so it should have no bearing on it whatsoever.

    They recommend against lapping, I think, because they are assuming you are cutting the valve seat and valve. If done correctly there is no need to lap, Suzuki states. Personally a light lapping even after recutting is used to confirm good contact area within specs listed in the manual. Also if the valve is not damaged, nor is the seat, and you are just going to use as is, then a lapping will help remove minor pitting without the expense of a full recut/grind.

    I am sure others will chime in its other reasons etc.

    And yea, it's easy for the budget to get out of control. While I'm in there I might as well do .........$$$$$$
    1978 Gs1085 compliments of Popy Yosh, Bandit 1200 wheels and front end, VM33 Smoothbores, Yosh exhaust, braced frame, ported polished head :cool:
    1983 Gs1100ESD, rebuild finished! Body paintwork happening winter 2017:D

    I would rather trust my bike to a technician that reads the service manual than some backyardigan that THINKS HE KNOWS how to fix things.

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      #3
      Ah, gotcha. I have a lot to learn about all this.
      1983 GS 1100 ESD :D

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        #4
        Technical Info posts that are deemed to be important or popular will be placed here for easier access. If you feel a post should be moved from the Technical Info forum to here then PM the Administrator with your request.

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          #5
          I've read through that thread a couple times, posplayer, thanks. Trying to balance what NEEDS to be done with what my wife will let me get away with...
          1983 GS 1100 ESD :D

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