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DT125R FORUM

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  4. Power valve o rings?

Power valve o rings?

Scheduled Pinned Locked Moved Engine
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  • S Offline
    S Offline
    SpookDog
    wrote on last edited by
    #7

    The kickstart side is straightforward, simple groove that fits perfectly. It’s the gearchange side that has no groove or place for a seal. The previous owner had the orange one just flopping around and a black smaller o ring squashed flat between the bush and the cover. Neither of those two are affecting a seal. I’ll check and see if there’s a paper gasket for that side. That would be enough of a seal...
    It’s frustrating when the last owner didn’t know what they were doing, it makes reassembly a bear!...

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    • CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by
      #8

      The pictures are a give away.

      The bush there has a groove cut out of it, the O-Ring sits inside the groove, the bush secures to powervalve in place.

      Always Originate, Never Pirate!

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      • S Offline
        S Offline
        SpookDog
        wrote on last edited by
        #9

        Sorry bud? Pics? I get a link with ‘all text’ access denied.
        Neither my bush or the cover have oring grooves on them, on that side. I wish I could post pics to show you what I mean but I just have a phone.

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        • CalumC Offline
          CalumC Offline
          Calum
          wrote on last edited by
          #10

          @SpookDog Oh Yeah 🤣 How annoying.

          Sorry, it looks like they are blocking that resource.

          It's a parts diagram showing you where the O-Rings go.

          https://www.fowlersparts.co.uk/main/img/assemblies/large/e2bbdd33f448b949dadded717beb407f.png?6

          I'll get it hosted elsewhere and link it in.

          Always Originate, Never Pirate!

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          • S Offline
            S Offline
            SpookDog
            wrote on last edited by
            #11

            Fowler’s don’t like hotlinking apparently!😊
            I found the diagram, unfortunately it is different from what I have fitted. I found I can affect a seal if I slip the oring over the end cap. Without it the whole cap/bush is very loose. It slops around loads! Whereas the other side is a good fit.
            I wasn’t even sure if it was original to the barrel. Who knows what butchery was done before. The PV has 3bn on it I think, yet the barrel is 3mb. I don’t know if there’s a difference. I’m still fumbling around in the dark. The only other 2strokes I’ve worked on were air cooled, ts er’s, and more shedloads of Vespa & Lambretta’s than I can recall. I don’t recall them having an oring between them 🙂
            Cheers bud!

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            • CalumC Offline
              CalumC Offline
              Calum
              wrote on last edited by
              #12

              The bushes wear out.

              There were different types of powervalves, not sure how they differed on the bush side of things though.

              Always Originate, Never Pirate!

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              • S Offline
                S Offline
                SpookDog
                wrote on last edited by
                #13

                One more question! Do you know what the black oring is for? I’ve got a full gasket set with black oring, but the only black oring I found was squashed into the PV and is obviously not right.
                It’s about 3/4 inch.

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                • S Offline
                  S Offline
                  SpookDog
                  wrote on last edited by
                  #14

                  Sorry, was busy thumb typing on a tiny screen!🤪
                  It’s not just the bush, the end cap it fits into also seems small. Plus it’s fixed, doesn’t move...
                  I’m guessing that the 3mb was a later servo operated valve? Totally different end cap on that side?...

                  CalumC 1 Reply Last reply
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                  • S SpookDog

                    Sorry, was busy thumb typing on a tiny screen!🤪
                    It’s not just the bush, the end cap it fits into also seems small. Plus it’s fixed, doesn’t move...
                    I’m guessing that the 3mb was a later servo operated valve? Totally different end cap on that side?...

                    CalumC Offline
                    CalumC Offline
                    Calum
                    wrote on last edited by
                    #15

                    @SpookDog the markings on the powervalve are misleading. I can't remember what is on the 3mb barrel. I do know that the two barrels take different valves, but I don't think the codes are representative.

                    Always Originate, Never Pirate!

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                    • NottsbikerN Offline
                      NottsbikerN Offline
                      Nottsbiker
                      wrote on last edited by
                      #16

                      Dont do what I did when I was being stupid and try and fit the o-rings onto the power valve itself lol

                      They go into the end caps and there is also an orange seal for the pulley end as well

                      I also got a black o-ring in my Athena gasket kit from PJME and have no idea where it goes

                      Wish it was the thermostat one as I need one but its the wrong size

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                      • CalumC Offline
                        CalumC Offline
                        Calum
                        wrote on last edited by
                        #17

                        Thermostat is paper gasket IIRC. Kellogs Cereal will do.

                        Always Originate, Never Pirate!

                        NottsbikerN 1 Reply Last reply
                        0
                        • S Offline
                          S Offline
                          SpookDog
                          wrote on last edited by
                          #18

                          Same as in my gasket set, it’s to small. You need a 33mm one for the thermostat. Get one from eBay. If you don’t have an account someone here will probably order it for you. It’ll be pennies ...

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                          • S Offline
                            S Offline
                            SpookDog
                            wrote on last edited by
                            #19

                            Sorry it’s 27mm Inner Diametre X 2.5 or 3mm Cross Section.

                            Calum, cheers for the info bud, it puts my mind to rest. I always worry more when learning a new engine...

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                            • CalumC Calum

                              Thermostat is paper gasket IIRC. Kellogs Cereal will do.

                              NottsbikerN Offline
                              NottsbikerN Offline
                              Nottsbiker
                              wrote on last edited by
                              #20

                              @Calum there is an o-ring under the thermostat itself with the gasket above that

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                              • S Offline
                                S Offline
                                SpookDog
                                wrote on last edited by
                                #21

                                The small oring in the gasket set is for the metal coolant pipe. It goes on the end that mates to the pump. Mysteries solved!...

                                1 Reply Last reply
                                1
                                • CalumC Offline
                                  CalumC Offline
                                  Calum
                                  wrote on last edited by
                                  #22

                                  Hhmm, yeah it's been such a long time since I've worked on that engine

                                  Always Originate, Never Pirate!

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                                  • S Offline
                                    S Offline
                                    SpookDog
                                    wrote on last edited by
                                    #23

                                    Hey! You weren’t wrong, there is a paper gasket. I was wrong about the oring though. It’s to big for the coolant pipe🙄

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