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    Power valve o rings?

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    • S
      SpookDog last edited by

      Where do the o rings fit, the orange ones? Also is there a gasket? Whoever built my engine last even had a black o ring sandwiched in. I really need a schematic or iTunes vid on how to reassemble the PV. I have the fixed PV with diamond end. It’s a 3bn engine with a 3mb barrel and head...
      Ta!

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      • S
        SpookDog last edited by

        That’s utube not iTunes! Ducking spellcheck!

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        • Calum
          Calum last edited by

          alt text

          You don't need a video to know how to disassemble it. It's like 5 pieces.

          Always Originate, Never Pirate!

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          • S
            SpookDog last edited by

            I don’t know where the seal fit is all. Putting it together and in is no problem. I just don’t think it was correct when I took it out..

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            • S
              SpookDog last edited by

              Or are the orange seals for servo PVs only?...

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              • Calum
                Calum last edited by

                No 19 are the seals. They sit in the bushes.

                Always Originate, Never Pirate!

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                • S
                  SpookDog last edited by

                  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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                  • Calum
                    Calum last edited by

                    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
                      SpookDog last edited by

                      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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                      • Calum
                        Calum last edited by

                        @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
                          SpookDog last edited by

                          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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                          • Calum
                            Calum last edited by

                            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
                              SpookDog last edited by

                              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
                                SpookDog last edited by

                                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?...

                                Calum 1 Reply Last reply Reply Quote 0
                                • Calum
                                  Calum @SpookDog last edited by

                                  @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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                                  • Nottsbiker
                                    Nottsbiker last edited by

                                    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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                                    • Calum
                                      Calum last edited by

                                      Thermostat is paper gasket IIRC. Kellogs Cereal will do.

                                      Always Originate, Never Pirate!

                                      Nottsbiker 1 Reply Last reply Reply Quote 0
                                      • S
                                        SpookDog last edited by

                                        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
                                          SpookDog last edited by

                                          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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                                          • Nottsbiker
                                            Nottsbiker @Calum last edited by

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

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