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    Athena 170 porting

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    dt 125 r athina 170 rebuild 170 athena
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    • L
      lllDennis last edited by

      Hi guys,

      So since i had a small oil leak i decided to rebuild my bike from the ground up (frame just got painted, everything is in pierced still).
      But I got curious and after some research offered a 170cc kit.

      When I did the research I saw that the ports are 3mm off for optimal power so i'm wondering if anyone has a guide or some tips to port a 170cc Athena kit to get that little bit extra. 😁

      Thanks in advance 👌

      markus.w 1 Reply Last reply Reply Quote 0
      • Calum
        Calum last edited by

        Someone had done it and documented it I thought. Have you had a look on this forum?

        Always Originate, Never Pirate!

        1 Reply Last reply Reply Quote 1
        • Calum
          Calum last edited by

          Check this thread out:
          https://dt125r.co.uk/topic/2164/ported-athena-170-kit-with-34mm-carb-and-athena-system

          Always Originate, Never Pirate!

          L 1 Reply Last reply Reply Quote 1
          • L
            lllDennis @Calum last edited by

            @Calum
            Yes i saw this one. The best solution would probably be a spacer but I would prefer a 'simple' porting job.

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

              @lllDennis A spacer would be far simpler. Run a mill over the top of the barrel and remove a few mm, then add a shim at the bottom.

              Always Originate, Never Pirate!

              L 1 Reply Last reply Reply Quote 1
              • L
                lllDennis @Calum last edited by

                @Calum
                I'll check it out, don't really have a Mill available. So i'll have to look for someone to do it for me. Spacers are custom build? Or you happen to know if anyone is selling them?

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

                  @lllDennis I'm sure I saw some on eBay a while back.

                  But that you won't need specialist tools. Buy a sheet of aluminium from eBay of a certain thickness, take the 170 base gasket as a template. Draw around and cut out.

                  It might not be pretty, but it doesn't have to be perfect. Just enough to act as a spacer. You finish it off with a file and take your time.

                  With regards to the mill, that is a really standard practice for engineering firms that work with heads for skimming. They'd probably be able to make the bottom spacer too. And will have a good understanding/confidence that what has been done is correct.

                  I'd want to see the results on the dyno before committing to anything yet though.

                  Also, you will need supporting mods to take advantage of this.

                  Always Originate, Never Pirate!

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

                    @Calum
                    I got a custom build pipe ready.
                    Zeeltronic also ready
                    All the jets for rejetting

                    I am planning to put the bike back together with the new pipe. Go to the dyno.
                    Change to the zeeltronic, prepare some maps. Go to the dyno
                    Change to the 170cc and after a solid break in back to the dyno.

                    To get a good idea of what gives the most difference 👌

                    This is a dyno from my current setup 👌
                    (Can't get the picture to work though)
                    img

                    L 1 Reply Last reply Reply Quote 1
                    • L
                      lllDennis @lllDennis last edited by

                      This post is deleted!
                      1 Reply Last reply Reply Quote 0
                      • Calum
                        Calum last edited by

                        alt text

                        Yeah smart. Sounds great.

                        Is that figure with the Athena as is?

                        Always Originate, Never Pirate!

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

                          @Calum
                          Stock dt125r with gianelli pipe and silencer.
                          And the destriction with the wire behind the Dash.

                          She pulls really well. But had a leaky connection between the silencer and pipe which lost a lot of power.
                          Also had a small oil leak at the shift lever. So decided to rebuild the while bike while waiting on my custom one I ordered from Henriques

                          Calum 1 Reply Last reply Reply Quote 1
                          • markus.w
                            markus.w @lllDennis last edited by

                            @lllDennis barrel spacers are readily available on eBay for about £10 each in varying thicknesses. Not sure about 3mm but you can use 2 1.5mm spacers.

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

                              @lllDennis That looks really good tbf.

                              I'd say that's probably better than my Ported 125 DTR with Zeel etc.

                              I would be interested in seeing how the stock 170 Athena barrel is by comparison.

                              My RS is very quick, however just looking at the curves on yours, it would have the RS low down. My bike is like unusable below 6K 🤣 Pretty sure the powervalve doesn't work either so it tapers off at 10K. Still miles faster than my DT though.

                              Always Originate, Never Pirate!

                              L 1 Reply Last reply Reply Quote 0
                              • L
                                lllDennis @markus.w last edited by lllDennis

                                @markus-w
                                I'll look into this. Now that i think about it the spacer is not that difficult we have a CNC machine at work to build electrical panels that van do this no problem.
                                Just have to find a mill now.

                                1mm enough? Or better with 1.5mm, 2mm? I only found 1mm on eBay 🤔.
                                Honestly I have no idea 🙃

                                markus.w 1 Reply Last reply Reply Quote 0
                                • L
                                  lllDennis @Calum last edited by

                                  @Calum
                                  I got very lucky. I bought it 6 years ago and looking back it was the deal of a lifetime. By far the best 125 I could've bought. And I got it very cheap 👌

                                  Calum 1 Reply Last reply Reply Quote 1
                                  • Calum
                                    Calum @lllDennis last edited by

                                    @lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is...

                                    Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one.

                                    Always Originate, Never Pirate!

                                    MadGyver 1 Reply Last reply Reply Quote 0
                                    • markus.w
                                      markus.w @lllDennis last edited by

                                      @lllDennis i have the Athena 170 kit on mine, I'm happy with performance but I have heard that the ports are 3mm out so was looking to raise it 3 mm with 2 1.5mm spacers and skim the top. They were on eBay must have sold out. but, what I'm now looking into is a long stroke crankshaft and only today BARacing of Portugal have advertised on Facebook 2 new crankshafts that are a direct fit, one is a 53mm stroke which would raise port timing by 2.7mm and other is 54mm so a 3.7mm raise, Standard stroke being 50.3. I read they need to be raised by at least 3mm so I'm guessing the 54 would be best but I have messaged then for advice on this and prices so will let you know if you're interested. probably an expensive way but I'd say by far the best way also would increase cc to about 185.

                                      L 1 Reply Last reply Reply Quote 1
                                      • L
                                        lllDennis @markus.w last edited by

                                        @markus-w
                                        That sounds real nice. Please keep me up to date 👌

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

                                          @calum said in Athena 170 porting:

                                          @lllDennis I read that the port timings were off by 3mm because apparently the barrel was based off a dtr200. How true that is...

                                          Would love to see before and after dyno pulls though. See how the stock Athena compares to a modified one.

                                          I have compared Athena 170 kit vs 3MB P (and 2RH) cylinders, the only 2 things that's off the athena kit is the piston taller than the stock,the ports are exact copy off the 3MB just a bit wider and the c port is little lower and matches more a 2RH cylinder

                                          The 170 is a mix between the 200cc casing (for the cooling canals and ypvs location) and 125 portmap internally.I searched for a piston that has the dimensions of the 56mm and with bore of 65mm but there is not,only some aftermarket forged that are max 61mm have the right piston height (pin to top).

                                          1 Reply Last reply Reply Quote 1
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