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DT125R FORUM

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  4. Most abused dt refurb

Most abused dt refurb

Scheduled Pinned Locked Moved DTR
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  • declanD declan

    @markus-w I can't help you out too much bud the wheels were just a quick and dirty job, originally I sprayed my rims Matt black no primer no lacquer and it adhered almost perfect to them I went over that with a gold brush on paint rustoleum I think it was and that adheres to anything then I just brushed satin black over that I intend on doing them properly at some point, if I were doing it without powder coating I would use a self etching primer cover the chrome fully them just pick a good quality paint of your choice and do light coats one 500ml can should be enough for both wheels providing you do light costs I personally wouldn't bother with lacquer but that's your call.

    markus.wM Offline
    markus.wM Offline
    markus.w
    wrote on last edited by
    #92

    @declan thank you. 👍

    1 Reply Last reply
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    • declanD Offline
      declanD Offline
      declan
      wrote on last edited by declan
      #93

      alt text

      Starting to take shape now got a lot of wiring to clean up.

      declanD 1 Reply Last reply
      1
      • declanD declan

        alt text

        Starting to take shape now got a lot of wiring to clean up.

        declanD Offline
        declanD Offline
        declan
        wrote on last edited by
        #94

        hey guys so it was test fire fast today and after a ton of kicking it ran twice for a few secs it was very weak I've narrowed it down to a weak spark the spark is blue but even if I hold the plug it doesent shock me nor if I put my finger in the ht cap the stator was tested as good not too long ago I will have to re check that I can't see anything obvious on the cdi side of things, but my wiring loom is bad a lot of connectors that just don't have anything connected mostly bullet connectors behind the headlight besides the kill switch which I also don't have is there any wires not including the key switch that can ground and weaken spark

        declanD 1 Reply Last reply
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        • declanD declan

          hey guys so it was test fire fast today and after a ton of kicking it ran twice for a few secs it was very weak I've narrowed it down to a weak spark the spark is blue but even if I hold the plug it doesent shock me nor if I put my finger in the ht cap the stator was tested as good not too long ago I will have to re check that I can't see anything obvious on the cdi side of things, but my wiring loom is bad a lot of connectors that just don't have anything connected mostly bullet connectors behind the headlight besides the kill switch which I also don't have is there any wires not including the key switch that can ground and weaken spark

          declanD Offline
          declanD Offline
          declan
          wrote on last edited by
          #95

          @declan Relative false alarm guys the Chinese dt125r coil pack i bought a year or so ago and only rode on once was dead I swapped it to the oem one that i thought was dead and it fired right up, y'know there's a lesson in here somewhere

          CalumC 1 Reply Last reply
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          • declanD declan

            @declan Relative false alarm guys the Chinese dt125r coil pack i bought a year or so ago and only rode on once was dead I swapped it to the oem one that i thought was dead and it fired right up, y'know there's a lesson in here somewhere

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #96

            @declan I bought one of those "Racing" coils. Nothing but problems. Since fitted genuine 3WM Coil now runs fine.

            Always Originate, Never Pirate!

            declanD 1 Reply Last reply
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            • CalumC Calum

              @declan I bought one of those "Racing" coils. Nothing but problems. Since fitted genuine 3WM Coil now runs fine.

              declanD Offline
              declanD Offline
              declan
              wrote on last edited by
              #97

              @calum I've used all manor of un branded Chinese stuff and still do but anything Chinese that specifically says it fits the dt parts wise has been absolute crap

              declanD 1 Reply Last reply
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              • declanD declan

                @calum I've used all manor of un branded Chinese stuff and still do but anything Chinese that specifically says it fits the dt parts wise has been absolute crap

                declanD Offline
                declanD Offline
                declan
                wrote on last edited by declan
                #98

                The bike runs decent but I still have play in the stator side crank even though it has brand new koyo mains is it possible the crank has worn down somehow over the years, it was all tight when I fitted them and it's only ran for around 3 minutes and I have a top end rattle I can't find any cause for this piston fits good no compression change powervalve seems fine it didn't have this sound before the only thing that's channged are new mains new piston and v force reeds it doesent sound like the crank I'm also using a thinner base gasket but surely that's not enough to cause issues?

                declanD 1 Reply Last reply
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                • declanD declan

                  The bike runs decent but I still have play in the stator side crank even though it has brand new koyo mains is it possible the crank has worn down somehow over the years, it was all tight when I fitted them and it's only ran for around 3 minutes and I have a top end rattle I can't find any cause for this piston fits good no compression change powervalve seems fine it didn't have this sound before the only thing that's channged are new mains new piston and v force reeds it doesent sound like the crank I'm also using a thinner base gasket but surely that's not enough to cause issues?

                  declanD Offline
                  declanD Offline
                  declan
                  wrote on last edited by
                  #99

                  The play in the flywheel feels the same as it's always been I rode it for years with the same play so I'm assuming the crank surface might have worn down, when it's running and I put my finger on the plastic pv pulley there's a deep sounding impact noise as far as I'm aware it's always done that is that normal?

                  S 1 Reply Last reply
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                  • declanD declan

                    The play in the flywheel feels the same as it's always been I rode it for years with the same play so I'm assuming the crank surface might have worn down, when it's running and I put my finger on the plastic pv pulley there's a deep sounding impact noise as far as I'm aware it's always done that is that normal?

                    S Offline
                    S Offline
                    SpookDog
                    wrote on last edited by SpookDog
                    #100

                    @declan

                    Is the piston over 57mm? Sometimes the power valve needs grinding to profile so it doesn’t hit the piston. The same with the head and the head gasket.
                    Have you adjusted the power valve position and/or gotten a rebore very recently?

                    The new bearings should eliminate any play. Are you sure the flywheel is tight on the crank? Do you have the thick washer fitted under the nut?
                    If you undo the nut and the flywheel is anything other than on there tight and needing a puller to remove, there’s something wrong...

                    I use a large flathead screwdriver to check for main bearing play on the flywheel side. Very gentle up and down pressure shows any real wear. Anything else is just flex in the shaft...

                    declanD 2 Replies Last reply
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                    • S SpookDog

                      @declan

                      Is the piston over 57mm? Sometimes the power valve needs grinding to profile so it doesn’t hit the piston. The same with the head and the head gasket.
                      Have you adjusted the power valve position and/or gotten a rebore very recently?

                      The new bearings should eliminate any play. Are you sure the flywheel is tight on the crank? Do you have the thick washer fitted under the nut?
                      If you undo the nut and the flywheel is anything other than on there tight and needing a puller to remove, there’s something wrong...

                      I use a large flathead screwdriver to check for main bearing play on the flywheel side. Very gentle up and down pressure shows any real wear. Anything else is just flex in the shaft...

                      declanD Offline
                      declanD Offline
                      declan
                      wrote on last edited by
                      #101

                      @spookdog thick washer is not installed since ive lost it but there's enough thread that its not needed flywheel is tight and fitted correctly, removed the cylinder earlier no damage or marks on piston or rings no sign of detonation i fitted an oem thickness base gasket while i was there nothing wrong with the rod or bearings wrist pin is good

                      1 Reply Last reply
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                      • S SpookDog

                        @declan

                        Is the piston over 57mm? Sometimes the power valve needs grinding to profile so it doesn’t hit the piston. The same with the head and the head gasket.
                        Have you adjusted the power valve position and/or gotten a rebore very recently?

                        The new bearings should eliminate any play. Are you sure the flywheel is tight on the crank? Do you have the thick washer fitted under the nut?
                        If you undo the nut and the flywheel is anything other than on there tight and needing a puller to remove, there’s something wrong...

                        I use a large flathead screwdriver to check for main bearing play on the flywheel side. Very gentle up and down pressure shows any real wear. Anything else is just flex in the shaft...

                        declanD Offline
                        declanD Offline
                        declan
                        wrote on last edited by
                        #102

                        @spookdog piston is 56.90 no contact with the valve

                        D 1 Reply Last reply
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                        • declanD declan

                          @spookdog piston is 56.90 no contact with the valve

                          D Offline
                          D Offline
                          DTR+NSR
                          wrote on last edited by
                          #103

                          The power valves knock, when the bushes wear. But the valves also seem to wear aswell. Also the right hand power valve cap isn't a great design, having only one fixing point. Probably why Yamaha changed the design of the power valve on the 4fu cylinders.

                          declanD 1 Reply Last reply
                          1
                          • D DTR+NSR

                            The power valves knock, when the bushes wear. But the valves also seem to wear aswell. Also the right hand power valve cap isn't a great design, having only one fixing point. Probably why Yamaha changed the design of the power valve on the 4fu cylinders.

                            declanD Offline
                            declanD Offline
                            declan
                            wrote on last edited by
                            #104

                            Okay engines stripped again cranks out and I can't find any issues both mains look good and bearing was tight on the crank and needed pressing out of the case

                            declanD 1 Reply Last reply
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                            • declanD declan

                              Okay engines stripped again cranks out and I can't find any issues both mains look good and bearing was tight on the crank and needed pressing out of the case

                              declanD Offline
                              declanD Offline
                              declan
                              wrote on last edited by
                              #105

                              The only potential issue I can see is the clutch side crank bearing is a slip fit to the crank it can be dropped on and pulled off the crank without any force what so ever does anyone remember if that's normal for the clutch side to be a slip fit

                              S 1 Reply Last reply
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                              • declanD declan

                                The only potential issue I can see is the clutch side crank bearing is a slip fit to the crank it can be dropped on and pulled off the crank without any force what so ever does anyone remember if that's normal for the clutch side to be a slip fit

                                S Offline
                                S Offline
                                SpookDog
                                wrote on last edited by
                                #106

                                Nether of them should be that easy. See if that bearing slides easy onto the other side of the crank. If it doesn’t then the clutch side bearing journal is worn...
                                If so you could try using fully hardening bearing lock. Like the Lockheed thread lock stuff...

                                declanD 1 Reply Last reply
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                                • S SpookDog

                                  Nether of them should be that easy. See if that bearing slides easy onto the other side of the crank. If it doesn’t then the clutch side bearing journal is worn...
                                  If so you could try using fully hardening bearing lock. Like the Lockheed thread lock stuff...

                                  declanD Offline
                                  declanD Offline
                                  declan
                                  wrote on last edited by declan
                                  #107

                                  @spookdog I tried one of the old bearings that I removed and that was the same, the bearing locker probably won't work it's only meant to stop spinning bearings this has lateral load so I'd imagine it would last a few seconds and then fail I'm gonna grab a used crank I just don't know what one to get some say the stroke used to be shorter but I don't know

                                  S 1 Reply Last reply
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                                  • declanD declan

                                    @spookdog I tried one of the old bearings that I removed and that was the same, the bearing locker probably won't work it's only meant to stop spinning bearings this has lateral load so I'd imagine it would last a few seconds and then fail I'm gonna grab a used crank I just don't know what one to get some say the stroke used to be shorter but I don't know

                                    S Offline
                                    S Offline
                                    SpookDog
                                    wrote on last edited by
                                    #108

                                    @declan

                                    It was only the early 1988 3bn barrels and cranks that had a different stroke. Get a later year one...

                                    1 Reply Last reply
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                                    • CalumC Offline
                                      CalumC Offline
                                      Calum
                                      wrote on last edited by
                                      #109

                                      That doesn't sound ideal. If the bearing comes off that easily then even bearing lock is just a temporary fix.

                                      Sounds like the journal needs to be machined and a spigot ring put in its place.

                                      Always Originate, Never Pirate!

                                      declanD 1 Reply Last reply
                                      0
                                      • CalumC Calum

                                        That doesn't sound ideal. If the bearing comes off that easily then even bearing lock is just a temporary fix.

                                        Sounds like the journal needs to be machined and a spigot ring put in its place.

                                        declanD Offline
                                        declanD Offline
                                        declan
                                        wrote on last edited by
                                        #110

                                        @calum yeah finding an early crank for cheap probably won't be easy either I'm thinking get a later crank and double up on my base gaskets or cut a base gasket thats thicker to set my squish

                                        CalumC 1 Reply Last reply
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                                        • declanD declan

                                          @calum yeah finding an early crank for cheap probably won't be easy either I'm thinking get a later crank and double up on my base gaskets or cut a base gasket thats thicker to set my squish

                                          CalumC Offline
                                          CalumC Offline
                                          Calum
                                          wrote on last edited by
                                          #111

                                          @declan why don't you just get a 3MB and call it a day.

                                          Always Originate, Never Pirate!

                                          declanD 1 Reply Last reply
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