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How do you know powervalves need attention?

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  • How do you know powervalves need attention?

    (Question sparked by Thro's comment in Blacky's thread) How do you know when your rgv's powervalves need replacing? Does the bike start lacking in power? Is it a gradual thing or do they just break?
    RR #137

    Supported by [/IMG]

  • #2
    The just break.
    Then fall into your engine and seize it.

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    • #3
      You don't, they should be checked at each maintenance period and serviced accordingly.

      Moving parts with push pull operation and mated metal surfaces always require regular maintenance.

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      • #4
        Originally posted by Desmogod View Post
        The just break.
        Then fall into your engine and seize it.
        Oh! Guess I would find out pretty quick then!

        Originally posted by nath View Post
        You don't, they should be checked at each maintenance period and serviced accordingly.

        Moving parts with push pull operation and mated metal surfaces always require regular maintenance.
        I have sooo much to learn.....
        RR #137

        Supported by [/IMG]

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        • #5
          You pull them out and inspect them.

          its not a hugely complicated job...


          What happens is that the pin that goes through the middle valve "just breaks" (and then what desmo described).

          What you're looking for is cracks etc - early warning signs that it is going to break soon.

          If you can afford it, get aftermarket billet centres... they eliminate this problem.
          “Crashing is shit for you, shit for the bike, shit for the mechanics and shit for the set-up,” Checa told me a while back. “It’s a signal that you are heading in the wrong direction. You want to win but crashing is the opposite. It’s like being in France when you want to go to England and when you crash you go to Spain. That way you’ll never get to England!” -- Carlos Checa

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          • #6
            There are several problems with the stock valves, it's not all about the pin.

            centre blade pin hole elongates, causing the PV to move further into the cylinder

            the collar on the fixed blade can break

            centre blade can crack through at the pin hole and completely fall into the cylinder

            Best to pull the lot out, check all blades, clean and replace if necessary.

            The hardest part is the 3 retaining screws, an impact driver will get these out.

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            • #7
              JD: I find pictures help... Those three puzzle pieces along the bottom of the pic form one of the powervalves (3 along the top)

              The lil pin bit you can see poking outta the valve piece in the centre is the bit Thro meant will snapsnap or elongate as Lee said

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              • #8
                ^^ ahh cheers, wasn't aware of the hole elongation :|

                edit:
                loz - the elongating bit is the groove the pin goes into I believe..
                “Crashing is shit for you, shit for the bike, shit for the mechanics and shit for the set-up,” Checa told me a while back. “It’s a signal that you are heading in the wrong direction. You want to win but crashing is the opposite. It’s like being in France when you want to go to England and when you crash you go to Spain. That way you’ll never get to England!” -- Carlos Checa

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                • #9
                  Hokay, I misread but that makes more sense

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                  • #10
                    Nah, the actual centre blade hole elongates, so the pin simply falls out. The outer blades do suffer elongation as well but I haven't seen/read of a failure because of it. It's always been the centre blade pin or hole, or the collar on the fixed blade, that cause the problems.

                    The photos lozzle has posted are CR valves with a billet centre. If you can afford these they are very good and cheaper than a new OEM set. The AUD > GBP is good at the moment, I am on the verge of buying another set for the rs250 if the AUD hits 0.50 GBP.

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                    • #11
                      Anyone ridden a bike with the valves wired open and one with working valves back to back?

                      Do you lose anything worth keeping between say 8k and 10k?
                      “Crashing is shit for you, shit for the bike, shit for the mechanics and shit for the set-up,” Checa told me a while back. “It’s a signal that you are heading in the wrong direction. You want to win but crashing is the opposite. It’s like being in France when you want to go to England and when you crash you go to Spain. That way you’ll never get to England!” -- Carlos Checa

                      Comment


                      • #12
                        The valves in my RGV had the pin hole elongated - made into a slightly oval shape. As soon as I pulled them out they fell to bits, so lucky I guess.

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                        • #13
                          Originally posted by thro View Post
                          Anyone ridden a bike with the valves wired open and one with working valves back to back?

                          Do you lose anything worth keeping between say 8k and 10k?

                          I originally had my valves set up to open earlier than normal, then set it up properly.

                          I've changed it back to open earlier than normal again cos I reckon it feels more fun...

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                          • #14
                            So what causes that ? just the friction on the round part against the barrel with the cable pulling on the center section ?

                            Would a low friction coating help in any way ?

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                            • #15
                              so you have adjusted them slightly open to begin with?

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