Skip to content
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Skins
  • Light
  • Cerulean
  • Cosmo
  • Flatly
  • Journal
  • Litera
  • Lumen
  • Lux
  • Materia
  • Minty
  • Morph
  • Pulse
  • Sandstone
  • Simplex
  • Sketchy
  • Spacelab
  • United
  • Yeti
  • Zephyr
  • Dark
  • Cyborg
  • Darkly
  • Quartz
  • Slate
  • Solar
  • Superhero
  • Vapor

  • Default (Slate)
  • No Skin
Collapse
Brand Logo

DT125R FORUM

  1. Home
  2. Technical Zone
  3. Engine
  4. Makita Piston

Makita Piston

Scheduled Pinned Locked Moved Engine
20 Posts 5 Posters 893 Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • CalumC Calum

    I wouldn't assume anything. Checking the ring gap will take you 60 seconds per ring.

    It's literally just placing the rings at the top of the bore. Use the piston to push it a few centimetres in and making sure it's square. Then using a feeler guage to measure the gap where the rings butt. It should reside within tolerance.

    I find the Wossner ones always supply one ring out of spec. Presumably so you can fine tune it yourself.

    Do that for both rings make sure they are tip top. Then whack them in and away you go.

    A Offline
    A Offline
    Arild
    wrote on last edited by
    #5

    @Calum

    Hey Calum, where can these tolerences be found? I suppose its in the service manual? I dont own a manual but maybe its time i pull the trigger on one

    D 1 Reply Last reply
    0
    • A Arild

      @Calum

      Hey Calum, where can these tolerences be found? I suppose its in the service manual? I dont own a manual but maybe its time i pull the trigger on one

      D Offline
      D Offline
      DTR+NSR
      wrote on last edited by
      #6

      @Arild 0.30 - 0.45mm you'll want a decent small file. And only file inwards towards the centre of the ring. I hold the file in a vice and slide the ring along the jaws of the vice to help keep it all square as well.

      A 1 Reply Last reply
      0
      • S SpookDog

        Yeah. Mitaka. I called it something entirely different in the thread title and edited it to Makita. How embarrassing?!!

        The barrel and piston have just come back from PJME so I trust the tolerance, ect. The barrel is a 3MB and it says TZR on the piston box. Iโ€™ve never had one like this before but I have seen them online in pics, ect.
        The piston that was in before was a wossner. Both the rings looked identical, so I donโ€™t really know what to make of it all. Just want to get it right, what with being the sixteenth โ€˜registeredโ€™ owner. I feel I have a duty of care for the old plodder ๐Ÿ˜‡

        declanD Offline
        declanD Offline
        declan
        wrote on last edited by
        #7

        @SpookDog ive installed one and left one out canโ€™t remember which bikes but the dt probably has one and Iโ€™m sure I tried one with and without on an am6 engine and it appeared to make no difference I donโ€™t actually know what itโ€™s for most people donโ€™t install them.

        1 Reply Last reply
        0
        • D DTR+NSR

          @Arild 0.30 - 0.45mm you'll want a decent small file. And only file inwards towards the centre of the ring. I hold the file in a vice and slide the ring along the jaws of the vice to help keep it all square as well.

          A Offline
          A Offline
          Arild
          wrote on last edited by
          #8

          @DTR-NSR

          Thanks mate๐Ÿ‘

          1 Reply Last reply
          0
          • S Offline
            S Offline
            SpookDog
            wrote on last edited by
            #9

            Soooo, itโ€™s an expander ring, for bores that have a bit too much clearance. Goes behind the thinner ring, on the bottom of the piston. Not recommended to be fitted if you have a nice tight fresh bore...
            Got an email from PJME

            declanD 1 Reply Last reply
            0
            • S SpookDog

              Soooo, itโ€™s an expander ring, for bores that have a bit too much clearance. Goes behind the thinner ring, on the bottom of the piston. Not recommended to be fitted if you have a nice tight fresh bore...
              Got an email from PJME

              declanD Offline
              declanD Offline
              declan
              wrote on last edited by
              #10

              @SpookDog moar compression!! Will do 109 in 4th gear with that in then

              1 Reply Last reply
              0
              • S Offline
                S Offline
                SpookDog
                wrote on last edited by
                #11

                @declan
                Wow, I wish I lived in the same reality as you...
                I think ๐Ÿค”

                declanD 1 Reply Last reply
                0
                • CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by Calum
                  #12

                  I mean, typically that's how it goes. The higher the compression the more power. Typically.... You need fueling and ignition timing to accommodate.

                  Always Originate, Never Pirate!

                  1 Reply Last reply
                  0
                  • S SpookDog

                    @declan
                    Wow, I wish I lived in the same reality as you...
                    I think ๐Ÿค”

                    declanD Offline
                    declanD Offline
                    declan
                    wrote on last edited by
                    #13

                    @SpookDog ๐Ÿ‘Œ

                    D 1 Reply Last reply
                    0
                    • declanD declan

                      @SpookDog ๐Ÿ‘Œ

                      D Offline
                      D Offline
                      DTR+NSR
                      wrote on last edited by
                      #14

                      When my dt was running 225psi it had incredible midrange but wouldn't rev high.

                      1 Reply Last reply
                      0
                      • CalumC Offline
                        CalumC Offline
                        Calum
                        wrote on last edited by
                        #15

                        225PSI! Wow! That's mental.

                        Always Originate, Never Pirate!

                        D 1 Reply Last reply
                        0
                        • CalumC Calum

                          225PSI! Wow! That's mental.

                          D Offline
                          D Offline
                          DTR+NSR
                          wrote on last edited by
                          #16

                          @Calum that was a cold engine aswell! That's with +1mm over bore. Running a mick abbey modded head. Which is quite a few cc's less volume than stock 3mb.
                          Runing two base gaskets and a spacer plate now. To lower the compression which has also raised the port timing. I miss the heaps of midrange but not the bruised foot from kickstarting it lol.

                          1 Reply Last reply
                          0
                          • CalumC Offline
                            CalumC Offline
                            Calum
                            wrote on last edited by
                            #17

                            Yeah I bet ๐Ÿคฃ

                            Always Originate, Never Pirate!

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

                              @declan
                              Sorry, didnโ€™t mean to offend. Plus I gave ๐Ÿ‘ƒ๐Ÿ‘Œ up a looooong time ago! ๐Ÿ™‚

                              In all seriousness, Iโ€™d like to know what the cc of a 3MB head is? Mine had to be reprofiled to get rid of piston ring explosion marks and Iโ€™m not sure if it was skimmed to the point that it kept the same compression ratio

                              D 1 Reply Last reply
                              0
                              • S SpookDog

                                @declan
                                Sorry, didnโ€™t mean to offend. Plus I gave ๐Ÿ‘ƒ๐Ÿ‘Œ up a looooong time ago! ๐Ÿ™‚

                                In all seriousness, Iโ€™d like to know what the cc of a 3MB head is? Mine had to be reprofiled to get rid of piston ring explosion marks and Iโ€™m not sure if it was skimmed to the point that it kept the same compression ratio

                                D Offline
                                D Offline
                                DTR+NSR
                                wrote on last edited by
                                #19

                                @SpookDog I measured one of my heads at 13cc, unfortunately can't remember which. The dome of the +1mm mitaka piston measures at 3.5cc though : p

                                1 Reply Last reply
                                0
                                • S Offline
                                  S Offline
                                  SpookDog
                                  wrote on last edited by
                                  #20

                                  Cheers bud, thatโ€™s something to work with. Iโ€™ve got a good 3bn, my reworked 3mb and another 3mb (that I forgot about till now) that is battle~scarred but otherwise original.

                                  1 Reply Last reply
                                  0
                                  Reply
                                  • Reply as topic
                                  Log in to reply
                                  • Oldest to Newest
                                  • Newest to Oldest
                                  • Most Votes


                                  • Login

                                  • Don't have an account? Register

                                  • Login or register to search.
                                  • First post
                                    Last post
                                  0
                                  • Recent
                                  • Tags
                                  • Popular
                                  • Users
                                  • Groups