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DT125R FORUM

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  4. Coolant loss

Coolant loss

Scheduled Pinned Locked Moved Engine
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  • D DTR+NSR

    @spookdog if you look at the under side of the cap you'll see a little metal washer that you can pull down, that's spring loaded. When your coolant cools and contracts, it creates a vacuum pulling down that washer allowing coolant to flow back in to the rad.
    Not had great success with copper gaskets myself, tend to be alot thicker as well, lowering the compression.

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    SpookDog
    wrote on last edited by
    #7

    @dtr-nsr
    Nice! I see what you mean now and can make sense of it in my mind. It was bugging me not understanding how it works...

    I believe that you’re supposed to re~torque the head nuts again after a certain interval/good run? I think I may of omitted to do this 🙄 it was such a long time between fitting the head and riding the bike or bringing it up to temp that I can’t be sure. I can see the path where it burned off the black coating from the gasket. I blame myself rather than Athena 🙂

    I’ve got a 0.5 & a 1mm copper gasket. I’m gonna try the .5 cause the head is 0.5mm deep to the squish. It’ll give me something to do till I get another Athena...

    MadGyverM 1 Reply Last reply
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    • S SpookDog

      @dtr-nsr
      Nice! I see what you mean now and can make sense of it in my mind. It was bugging me not understanding how it works...

      I believe that you’re supposed to re~torque the head nuts again after a certain interval/good run? I think I may of omitted to do this 🙄 it was such a long time between fitting the head and riding the bike or bringing it up to temp that I can’t be sure. I can see the path where it burned off the black coating from the gasket. I blame myself rather than Athena 🙂

      I’ve got a 0.5 & a 1mm copper gasket. I’m gonna try the .5 cause the head is 0.5mm deep to the squish. It’ll give me something to do till I get another Athena...

      MadGyverM Offline
      MadGyverM Offline
      MadGyver
      wrote on last edited by
      #8

      @spookdog Anneal the copper gasket first and use a high temp copper based gasket spray (I use from Permatex).

      I need my tools and a pile of junk.....

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      • MadGyverM MadGyver

        @spookdog Anneal the copper gasket first and use a high temp copper based gasket spray (I use from Permatex).

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        SpookDog
        wrote on last edited by
        #9

        Curiosity!
        Which type of Athena gasket are people using, the metal or composite type?...

        MadGyverM 1 Reply Last reply
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        • S SpookDog

          Curiosity!
          Which type of Athena gasket are people using, the metal or composite type?...

          MadGyverM Offline
          MadGyverM Offline
          MadGyver
          wrote on last edited by
          #10

          @spookdog The composite one mostly.I use a custom copper gasket.

          I need my tools and a pile of junk.....

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          • MadGyverM MadGyver

            @spookdog The composite one mostly.I use a custom copper gasket.

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            SpookDog
            wrote on last edited by
            #11

            Are the composite gaskets much thicker than the metal shim gaskets? I’m wondering about it affecting the squish band gap.
            I got 200 miles out of the Chinese one I had kicking around. I have to try the copper one now, with Hylomar to fill the gaps. Just till I get some pennies in my pockets. Or unless the copper on is a keeper 🙂

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            • S SpookDog

              Are the composite gaskets much thicker than the metal shim gaskets? I’m wondering about it affecting the squish band gap.
              I got 200 miles out of the Chinese one I had kicking around. I have to try the copper one now, with Hylomar to fill the gaps. Just till I get some pennies in my pockets. Or unless the copper on is a keeper 🙂

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              SpookDog
              wrote on last edited by
              #12

              This is weird, I was seeing lots of gaskets made of composite for dtr’s (125) made by Athena. Now i can only find one and that looks like they used a 170 pic for the listing.
              Do Athena make composite gaskets for a 125? Or is it just 170?...

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              • S SpookDog

                This is weird, I was seeing lots of gaskets made of composite for dtr’s (125) made by Athena. Now i can only find one and that looks like they used a 170 pic for the listing.
                Do Athena make composite gaskets for a 125? Or is it just 170?...

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                SpookDog
                wrote on last edited by
                #13

                @everyone

                What size torque wrench are people using to torque down the cylinder head while in the frame?
                I only have a 1/2inch drive that is way to big to fit...

                CalumC 1 Reply Last reply
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                • S SpookDog

                  @everyone

                  What size torque wrench are people using to torque down the cylinder head while in the frame?
                  I only have a 1/2inch drive that is way to big to fit...

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #14

                  @spookdog 1/4", but really the engine needs to be out to do it properly.

                  Always Originate, Never Pirate!

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                  • CalumC Calum

                    @spookdog 1/4", but really the engine needs to be out to do it properly.

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                    SpookDog
                    wrote on last edited by
                    #15

                    @calum
                    Cheers bud...
                    2 nm’s is where my wrench kicks in. It’s too near the threshold for me to trust. If I want to do it right I really want new studs and dome nuts with washers.
                    I’ve never had troubles with single cylinder bikes before, then again none of them were liquid cooled...

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                    • S SpookDog

                      @calum
                      Cheers bud...
                      2 nm’s is where my wrench kicks in. It’s too near the threshold for me to trust. If I want to do it right I really want new studs and dome nuts with washers.
                      I’ve never had troubles with single cylinder bikes before, then again none of them were liquid cooled...

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                      SpookDog
                      wrote on last edited by
                      #16

                      Thoughts please!...

                      3 times now my head gasket has blown. The first time it was a good gasket with 3000 miles on it, the 2nd time it was a cheap Chinese job that was ‘used but not run’. 3rd time was using an unfamiliar copper gasket without the proper spray sealant, so the last 2 are on me.
                      Each time it failed in a different place, but! the weird thing is that it always failed on the upper, head side of the gasket. The bottom half was always sealed firmly to the barrel, with absolutely zero sign of leakage or blow by. Any ideas why?...

                      declanD CalumC 2 Replies Last reply
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                      • S SpookDog

                        Thoughts please!...

                        3 times now my head gasket has blown. The first time it was a good gasket with 3000 miles on it, the 2nd time it was a cheap Chinese job that was ‘used but not run’. 3rd time was using an unfamiliar copper gasket without the proper spray sealant, so the last 2 are on me.
                        Each time it failed in a different place, but! the weird thing is that it always failed on the upper, head side of the gasket. The bottom half was always sealed firmly to the barrel, with absolutely zero sign of leakage or blow by. Any ideas why?...

                        declanD Offline
                        declanD Offline
                        declan
                        wrote on last edited by
                        #17

                        @spookdog are you putting them the right way up?

                        1 Reply Last reply
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                        • S SpookDog

                          Thoughts please!...

                          3 times now my head gasket has blown. The first time it was a good gasket with 3000 miles on it, the 2nd time it was a cheap Chinese job that was ‘used but not run’. 3rd time was using an unfamiliar copper gasket without the proper spray sealant, so the last 2 are on me.
                          Each time it failed in a different place, but! the weird thing is that it always failed on the upper, head side of the gasket. The bottom half was always sealed firmly to the barrel, with absolutely zero sign of leakage or blow by. Any ideas why?...

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #18

                          @spookdog What!

                          What do you mean "Good gasket with 3000 miles on it"? Head gasket? They are not reusable.

                          The chinese ones simply don't work.

                          Just get a genuine or Athena gasket. Brand new, never fitted and use that.

                          Always Originate, Never Pirate!

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                          • CalumC Calum

                            @spookdog What!

                            What do you mean "Good gasket with 3000 miles on it"? Head gasket? They are not reusable.

                            The chinese ones simply don't work.

                            Just get a genuine or Athena gasket. Brand new, never fitted and use that.

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                            SpookDog
                            wrote on last edited by SpookDog
                            #19

                            @calum
                            It ran sweet for 3000 miles then blew. I didn’t reuse it. It was new & Athena. I just got another delivered today for under £13 which I thought was quite good...

                            Yeah, the up is on the up 🙂

                            its weird that they all blown at the head side of the gaskets...

                            Is my squish supposed to be less than a mm, with gasket included?...
                            The head was done by PJME 3000 miles ago. I’m thinking of maybe lapping it on a good bit of plate glass

                            CalumC 1 Reply Last reply
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                            • S SpookDog

                              @calum
                              It ran sweet for 3000 miles then blew. I didn’t reuse it. It was new & Athena. I just got another delivered today for under £13 which I thought was quite good...

                              Yeah, the up is on the up 🙂

                              its weird that they all blown at the head side of the gaskets...

                              Is my squish supposed to be less than a mm, with gasket included?...
                              The head was done by PJME 3000 miles ago. I’m thinking of maybe lapping it on a good bit of plate glass

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #20

                              @spookdog Was going to say!

                              Have you checked out...
                              https://dt125r.co.uk/topic/11/how-to-i-gentle-skim-your-head-barrel

                              Always Originate, Never Pirate!

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                              • CalumC Calum

                                @spookdog Was going to say!

                                Have you checked out...
                                https://dt125r.co.uk/topic/11/how-to-i-gentle-skim-your-head-barrel

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                                SpookDog
                                wrote on last edited by
                                #21

                                @calum

                                I’m gonna have to check it out. My brand new Athena gasket, correctly torqued down, blew again ☹️ Did about 100miles. Weird thing is that the bike ran the best ever after it let go. Crisp rev definition, no bogging down. I’m gonna have to compression test the engine next time. What range is good/normal!?

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