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    Rust inside brand new exhaust?!

    Hi.

    So I just received a brand new Marving exhaust for my GS550. Yay, looks nice right?:


    That's what I thought until I noticed this:

    And this:


    Same thing in all four pipes. Is this something that anyone on here tried before? Besides from being very disappointed by this on a brand new exhaust, I'm just curious as to if what may have caused this? Is this a returned exhaust or what? What would you guys do? Is this gonna have any big impact on the durability of the exhaust? I'm not exactly happy about it, but I've waited almost 2 months to get this and would like not to wait another 2

    #2
    My guess is the only way to stop the rust in that mild steel pipe is to get some exhaust soot on it. Personally I would run some acid magic through the inside, spray some WD-40 and mount them.
    That said I would call the supplier snd threaten to send them back unless they give you a pretty steep discount.

    Comment


      #3
      A bit of flash rust is all.
      What is acid magic?
      1983 GS 550 LD
      2009 BMW K1300s

      Comment


        #4
        Rust inside the pipes is normal. Even the OEM pipes rust on the inside. A lot of aftermarket pipes rust on the outside of the header pipes too, where 4:1 header pipes cluster together. Rust is the reason a lot of OEM and some aftermarket pipes have moved to stainless steel. Options are limited though.
        Ed

        To measure is to know.

        Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

        Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

        Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

        KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

        Comment


          #5
          I had to look up Acid Magic as well.
          Only 9 reviews but at least they are good ones.
          Acid Magic is a full strength muriatic-based product formulated to ship, use and store easier than standard muriatic acid. This revolutionary blend of proprietary ingredients offers the cleaning and pH reduction of powerful acids while providing increased usability.Find the ACID MAGIC MUR ACID GAL at Ace.
          2@ \'78 GS1000

          Comment


            #6
            The active ingredient in Acid Magic is hydrochloric acid. There are better options to derust steel, namely phosphoric acid. In the painting industry phosphoric acid is the material of choice to clean metal before painting. It leaves the metal with a mild phosphate coating too which helps ward off rust. HCl is harsh and more geared for extreme usage such as washing down bricks and concrete. I wouldn't use that stuff on a gas tank or exhaust system. In fact, I wouldn't use anything on the exhaust system since it's just going to rust again very quickly. Water vapor is a byproduct of combustion so the inside of the pipe will be exposed to water all the time and any rust you remove will just return.
            Ed

            To measure is to know.

            Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

            Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

            Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

            KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

            Comment


              #7
              Yes acid would etch and increase surface are thus accelerating rusting process.
              A lot of sulphur gets belched out a pipe. Its no wonder they rust.

              You see this a lot in short haul commuter cars especially in cold months.
              Pipe never gets clear of condensation which is a h2so4 solution.

              Trick is to drive long enough to get the pipe hot and relatively dry.
              1983 GS 550 LD
              2009 BMW K1300s

              Comment


                #8
                Trick is to drive long enough to get the pipe hot and relatively dry.
                Cool, now I know winding out my 550 on my 30ish-minute commute is for a good reason.

                Have to watch out for the law though.
                #1: 1979 GS 550 EC "Red" – Very first Bike / Overhaul thread        New here? ☛ Read the Top 10 Newbie mistakes thread
                #2: 1978 GS 550 EC "Blue" – Can't make it a donor / "Rebuild" thread     Manuals (and much more): See Cliff's homepage here
                #3: 2014 Moto Guzzi V7 II Racer – One needs a runner while wrenching
                #4: 1980 Moto Guzzi V65C – Something to chill

                Comment


                  #9
                  Originally posted by Cipher View Post
                  Yes acid would etch and increase surface are thus accelerating rusting process.
                  A lot of sulphur gets belched out a pipe. Its no wonder they rust.

                  You see this a lot in short haul commuter cars especially in cold months.
                  Pipe never gets clear of condensation which is a h2so4 solution.

                  Trick is to drive long enough to get the pipe hot and relatively dry.
                  The only point of the acid would be to get rid of the larger flakes that seem to be present. Yes it will flash rust again immediately which would be the reason to get something on there (WD-40) to inhibit the rust long enough to where he can get the pipe on the bike and run it and get it coated with some exhaust.

                  I have most of this stuff on hand, and can flush with the AcidMagic and just be done. No reason to spend $50 on materials as it is all going to be machts nix anyway.

                  Referring to Ed's suggesting of to leave a "mild phosphate coating", sure but it is not going to matter in the long term.

                  Last time I used the Acid magic to get rid of heavy rust on a gas tank sender, I washed it off and sprayed with DeOxit which provided a coating to stop the flash rust. This again is only a temporary solution till you an get it into the tank and the gas inhibits the rust.

                  Comment


                    #10
                    Sorry for the late replay. Thank you for the advice guys. I've sent them an email and waiting for the respons.

                    Comment


                      #11
                      Originally posted by 11csive View Post
                      Sorry for the late replay. Thank you for the advice guys. I've sent them an email and waiting for the respons.
                      I'm sure those of us left are "not holding their breath".

                      Comment

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