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DT125R FORUM

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  4. So Close!...

So Close!...

Scheduled Pinned Locked Moved DTR
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  • S SpookDog

    This always bugged me! There is not supposed to be a ‘step’ there, eh?

    alt text

    These are the cases I’m using now. I matched both sides before rebuilding. Could this be problematic? 2 different unmatched cases?...

    S Offline
    S Offline
    SpookDog
    wrote on last edited by SpookDog
    #62

    Best I’ve had! After 15 mile test run...

    alt text

    alt text

    Same plug, different light...

    Was revving ‘quite’ cleanly up to 9000rpm on 1/2~3/4 throttle. Just a little snaggle @ 1/4 throttle...

    updated ran the engine up to temp for 15 mins on tickover and the plug was black and wet. I’m @ 1 & 1/2 turns on the airscrew. I will try up to 2 turns, then maybe go down to a .20 pilot jet. I have some genuine Mikuni ones now. The cheap fleabay ones are worse than a joke. I brought 10 varying from .10 upwards and they were all the same. Even though they were stamped 🙄

    CalumC 1 Reply Last reply
    1
    • S SpookDog

      Best I’ve had! After 15 mile test run...

      alt text

      alt text

      Same plug, different light...

      Was revving ‘quite’ cleanly up to 9000rpm on 1/2~3/4 throttle. Just a little snaggle @ 1/4 throttle...

      updated ran the engine up to temp for 15 mins on tickover and the plug was black and wet. I’m @ 1 & 1/2 turns on the airscrew. I will try up to 2 turns, then maybe go down to a .20 pilot jet. I have some genuine Mikuni ones now. The cheap fleabay ones are worse than a joke. I brought 10 varying from .10 upwards and they were all the same. Even though they were stamped 🙄

      CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by
      #63

      @spookdog Oh yeah, second photo is looking good 👍

      Always Originate, Never Pirate!

      S 1 Reply Last reply
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      • CalumC Calum

        @spookdog Oh yeah, second photo is looking good 👍

        S Offline
        S Offline
        SpookDog
        wrote on last edited by
        #64

        @Calum
        Cheers...

        I forgot to say, I blocked/bypassed the power jet as well. I was getting bad random bogging above 1/2 throttle with loads of smoke. It’s stopped so far. I just wanted to cut out as many variables as possible and tackle them one at a time. I even bubble wrapped the ignition control modules under the seat in case they were getting a bashing and it was electrical...

        Oil pump was definitely splurging

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        • S SpookDog

          @Calum
          Cheers...

          I forgot to say, I blocked/bypassed the power jet as well. I was getting bad random bogging above 1/2 throttle with loads of smoke. It’s stopped so far. I just wanted to cut out as many variables as possible and tackle them one at a time. I even bubble wrapped the ignition control modules under the seat in case they were getting a bashing and it was electrical...

          Oil pump was definitely splurging

          S Offline
          S Offline
          SpookDog
          wrote on last edited by
          #65

          Took it for a 70 mile test run today. The head gasket is holding in there!..

          As it was running well a day ago, I thought I’d put the needle down a notch (from middle) to the 4th notch down, where it’s supposed to be according to the manual. The plug is a richer chocolate colour but it started bogging again. So tomorrow it’s back to the 3rd, middle notch. Make sure it runs as smooth as it was before, then address the pilot jet/airscrew mixture...

          I’d never believed a single notch could cause so much change! Wish me luck...

          S 1 Reply Last reply
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          • S SpookDog

            Took it for a 70 mile test run today. The head gasket is holding in there!..

            As it was running well a day ago, I thought I’d put the needle down a notch (from middle) to the 4th notch down, where it’s supposed to be according to the manual. The plug is a richer chocolate colour but it started bogging again. So tomorrow it’s back to the 3rd, middle notch. Make sure it runs as smooth as it was before, then address the pilot jet/airscrew mixture...

            I’d never believed a single notch could cause so much change! Wish me luck...

            S Offline
            S Offline
            SpookDog
            wrote on last edited by
            #66

            more variables:

            Found 2 new potential problems: 1, the wires for the sidestand kill switch may of been crushed by the seat. 2, I had to fit an inline fuel filter because of the state of the tanks inside, it has been creating a ‘locked in place’ air bubble. I don’t know if it’s been affecting flow at high revs and causing ‘bogging’. I have managed to finesse the air out by holding the tank up and keeping the fuel line vertical...

            My next test ride will tell...

            1 Reply Last reply
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            • declanD Offline
              declanD Offline
              declan
              wrote on last edited by
              #67

              @spookdog air in the line is normal happens to a lot of bikes

              S 1 Reply Last reply
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              • declanD declan

                @spookdog air in the line is normal happens to a lot of bikes

                S Offline
                S Offline
                SpookDog
                wrote on last edited by SpookDog
                #68

                Best colour yet, ever! This is with the needle in the middle slot, also with the airscrew turned out 3 full turns. That is fully open when you look into the air jet!...

                alt text

                Below:
                This is the plug that’s been brought up to full temp on tickover only, remember that this is with the airscrew wound full out...

                alt text

                Wet n black! I don’t know why the standard 0.225 pilot jet is too rich on my particular bike, but it is. I have a 0.20 Mikuni jet I’m gonna try tomorrow. Wish me luck 👍
                🐾☠️🐾

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                • S SpookDog

                  Best colour yet, ever! This is with the needle in the middle slot, also with the airscrew turned out 3 full turns. That is fully open when you look into the air jet!...

                  alt text

                  Below:
                  This is the plug that’s been brought up to full temp on tickover only, remember that this is with the airscrew wound full out...

                  alt text

                  Wet n black! I don’t know why the standard 0.225 pilot jet is too rich on my particular bike, but it is. I have a 0.20 Mikuni jet I’m gonna try tomorrow. Wish me luck 👍
                  🐾☠️🐾

                  S Offline
                  S Offline
                  SpookDog
                  wrote on last edited by
                  #69

                  Found another potential yesterday, the long breather pipe that hangs down on the kickstart side leads to a hole at the top of the ‘tube’ that the needle jet fits into. (I guess it’s to let the fuel level go up and down inside the jet, equalising the pressure, maybe? Fluid won’t rise in a closed environment, like an upside down cup in water) where the slide housing joins there is potential for mischief. My gasket is so compressed I have to use sealant. I’ve tried hermatite red and silicon. The silicon was kinda vulcanised by the fuel at the bottom of the slide where the breather pipe join is. So I’m going with the red but I’ve had so many inconsistencies I really want a new gasket. Anyone know of?...
                  I think the vent has been causing some of the mid throttle bogging and inconsistency...

                  S 1 Reply Last reply
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                  • S SpookDog

                    Found another potential yesterday, the long breather pipe that hangs down on the kickstart side leads to a hole at the top of the ‘tube’ that the needle jet fits into. (I guess it’s to let the fuel level go up and down inside the jet, equalising the pressure, maybe? Fluid won’t rise in a closed environment, like an upside down cup in water) where the slide housing joins there is potential for mischief. My gasket is so compressed I have to use sealant. I’ve tried hermatite red and silicon. The silicon was kinda vulcanised by the fuel at the bottom of the slide where the breather pipe join is. So I’m going with the red but I’ve had so many inconsistencies I really want a new gasket. Anyone know of?...
                    I think the vent has been causing some of the mid throttle bogging and inconsistency...

                    S Offline
                    S Offline
                    SpookDog
                    wrote on last edited by
                    #70

                    Went down to a .20 pilot and it still ran wet plug with the airscrew fully out! Since put in a 17.5 and it ticks over well, the plug is still slightly black but not dripping wet at 1.5 turns...

                    The proof will be in a test ride though...

                    I’m using this thread as a memory diary, if I don’t write it down I forget!

                    S 1 Reply Last reply
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                    • S SpookDog

                      Went down to a .20 pilot and it still ran wet plug with the airscrew fully out! Since put in a 17.5 and it ticks over well, the plug is still slightly black but not dripping wet at 1.5 turns...

                      The proof will be in a test ride though...

                      I’m using this thread as a memory diary, if I don’t write it down I forget!

                      S Offline
                      S Offline
                      SpookDog
                      wrote on last edited by
                      #71

                      It’s running good on the 17.5 pilot at 1/4 turn out of the airscrew. Did a 70 mile test ride with loads of slow running, plug is dry, at last!! 🤪

                      S 1 Reply Last reply
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                      • S SpookDog

                        It’s running good on the 17.5 pilot at 1/4 turn out of the airscrew. Did a 70 mile test ride with loads of slow running, plug is dry, at last!! 🤪

                        S Offline
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                        SpookDog
                        wrote on last edited by
                        #72

                        Has anyone else had overheating problems the last couple hot days?

                        CalumC 1 Reply Last reply
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                        • S SpookDog

                          Has anyone else had overheating problems the last couple hot days?

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #73

                          @spookdog my dt runs SUPER hot. 90 degrees c. I think it's when the thermostat opens as it then drops to 79/80.

                          I run ecans waterless coolant which will make it run a tad hotter

                          Always Originate, Never Pirate!

                          S 1 Reply Last reply
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                          • CalumC Calum

                            @spookdog my dt runs SUPER hot. 90 degrees c. I think it's when the thermostat opens as it then drops to 79/80.

                            I run ecans waterless coolant which will make it run a tad hotter

                            S Offline
                            S Offline
                            SpookDog
                            wrote on last edited by SpookDog
                            #74

                            @calum
                            I’m not sure why you think that is super hot bud, 90* is perfect running temp I think. If it’s doing it while under load at high revs is even better! You’re running 200 twin radiators aren’t you?

                            I’ve managed to reign mine in a bit. I put another radiator on it that I managed to finesse back into usefulness. I straightened some fins and removed the outer edge of the worse with a Dremel type tool.
                            My old radiator had so many fins folded over on the inner side that it wasn’t funny! Why the inside gets the brunt of it I don’t know. I’d of thought that it would be the outer ‘wind in’ side that caught it?...

                            CalumC 1 Reply Last reply
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                            • S SpookDog

                              @calum
                              I’m not sure why you think that is super hot bud, 90* is perfect running temp I think. If it’s doing it while under load at high revs is even better! You’re running 200 twin radiators aren’t you?

                              I’ve managed to reign mine in a bit. I put another radiator on it that I managed to finesse back into usefulness. I straightened some fins and removed the outer edge of the worse with a Dremel type tool.
                              My old radiator had so many fins folded over on the inner side that it wasn’t funny! Why the inside gets the brunt of it I don’t know. I’d of thought that it would be the outer ‘wind in’ side that caught it?...

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #75

                              @spookdog It went mental on Sunday 100 degrees centigrade under very light riding. I came to a stop at the traffic lights and the engine just started to rev it's nuts off on its own. I killed the engine (nothing) turned the ignition switch off nothing. Had to kill the fuel in the end.

                              So yeah, it just seems to run WAY too hot that it's igniting on its own 😮

                              Always Originate, Never Pirate!

                              S 1 Reply Last reply
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                              • CalumC Calum

                                @spookdog It went mental on Sunday 100 degrees centigrade under very light riding. I came to a stop at the traffic lights and the engine just started to rev it's nuts off on its own. I killed the engine (nothing) turned the ignition switch off nothing. Had to kill the fuel in the end.

                                So yeah, it just seems to run WAY too hot that it's igniting on its own 😮

                                S Offline
                                S Offline
                                SpookDog
                                wrote on last edited by
                                #76

                                Since I’ve had the ‘new’ radiator on I’ve had a lot better temps during the hot days recently. I’ve swapped out the standard tailpipe for a BigOne that’s been laying around, this seems to be beneficial as well. It seems to be running even cooler. Not sure why...

                                The plugs been dry since I fitted the 17.5 pilot jet, the midrange seems good as well going by the plug. Top end/main jet is still buggered. The last two times I snapped the throttle open fully I had heatseize symptoms. Both times I whipped the clutch in and coasted to a stop, both times it started up straight away. I haven’t been in a position to recreate the symptoms to see if it was a genuine heat seazure (sp?) or a totall bogout due to main jet being wrong. It’s a 210 ATM, it was a 180 before...

                                Problem on top of problem after problem being an invisible problem 🤯

                                Oh well it’s all in fun and we live and learn while the World falls apart around us! 😜

                                S 1 Reply Last reply
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                                • S SpookDog

                                  Since I’ve had the ‘new’ radiator on I’ve had a lot better temps during the hot days recently. I’ve swapped out the standard tailpipe for a BigOne that’s been laying around, this seems to be beneficial as well. It seems to be running even cooler. Not sure why...

                                  The plugs been dry since I fitted the 17.5 pilot jet, the midrange seems good as well going by the plug. Top end/main jet is still buggered. The last two times I snapped the throttle open fully I had heatseize symptoms. Both times I whipped the clutch in and coasted to a stop, both times it started up straight away. I haven’t been in a position to recreate the symptoms to see if it was a genuine heat seazure (sp?) or a totall bogout due to main jet being wrong. It’s a 210 ATM, it was a 180 before...

                                  Problem on top of problem after problem being an invisible problem 🤯

                                  Oh well it’s all in fun and we live and learn while the World falls apart around us! 😜

                                  S Offline
                                  S Offline
                                  SpookDog
                                  wrote on last edited by
                                  #77

                                  Turns out it was heat seazures. 4 point seazure marks on piston, 1 bad enough to have ‘the look’ of sliding metal. More eating away of the piston crown and scoring to the barrel 🤨 it all happened before I changed the radiator. Oh well! We live and turn 🤪

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                                  • S SpookDog

                                    Turns out it was heat seazures. 4 point seazure marks on piston, 1 bad enough to have ‘the look’ of sliding metal. More eating away of the piston crown and scoring to the barrel 🤨 it all happened before I changed the radiator. Oh well! We live and turn 🤪

                                    D Offline
                                    D Offline
                                    DTR+NSR
                                    wrote on last edited by
                                    #78

                                    @spookdog heat seizure is all to do with your mixture being to lean, nothing to do with how well your cooling is working or not. A lean mixture will burn hotter aswell. Which was probably contributing to your over heating.

                                    1 Reply Last reply
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                                    • CalumC Offline
                                      CalumC Offline
                                      Calum
                                      wrote on last edited by
                                      #79

                                      Oh bummer, what's the damage

                                      Always Originate, Never Pirate!

                                      S 1 Reply Last reply
                                      0
                                      • CalumC Calum

                                        Oh bummer, what's the damage

                                        S Offline
                                        S Offline
                                        SpookDog
                                        wrote on last edited by SpookDog
                                        #80

                                        @calum
                                        Pics to come when I fix phone!

                                        Has anyone had dealings with Athena gaskets that are 3 layers fixed together with 2 brass rivets?...

                                        alt text

                                        Anyone? The outer 2 are black with the usual coating, while the centre 1 is silver...

                                        @Dtr&nsr
                                        It’s definitely heat caused, mostly my own ignorance
                                        I understand that mixture being lean can run too hot, but it wasn’t solely that. There was even plenty of oil in the barrel and around the crank. Although it is a bit sooty and scorched!...

                                        @Everyone
                                        I have problems with my temp gauge, normal running temp is showing at 5mm above the C (for Cold) and any variation above doesn’t really show very much. It was below the halfway mark when the head gasket blew!!
                                        The old radiator was a lot less efficient at dumping heat than the new one, it was OK when the ambient temp was not ‘heatwave hot’. The new one throws away BTU’s nicely.
                                        Ideally I’d like to adjust the temp gauge with a resistor or something, so as that ‘normal’ temp is in the middle of the gauge...

                                        D 1 Reply Last reply
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                                        • S SpookDog

                                          @calum
                                          Pics to come when I fix phone!

                                          Has anyone had dealings with Athena gaskets that are 3 layers fixed together with 2 brass rivets?...

                                          alt text

                                          Anyone? The outer 2 are black with the usual coating, while the centre 1 is silver...

                                          @Dtr&nsr
                                          It’s definitely heat caused, mostly my own ignorance
                                          I understand that mixture being lean can run too hot, but it wasn’t solely that. There was even plenty of oil in the barrel and around the crank. Although it is a bit sooty and scorched!...

                                          @Everyone
                                          I have problems with my temp gauge, normal running temp is showing at 5mm above the C (for Cold) and any variation above doesn’t really show very much. It was below the halfway mark when the head gasket blew!!
                                          The old radiator was a lot less efficient at dumping heat than the new one, it was OK when the ambient temp was not ‘heatwave hot’. The new one throws away BTU’s nicely.
                                          Ideally I’d like to adjust the temp gauge with a resistor or something, so as that ‘normal’ temp is in the middle of the gauge...

                                          D Offline
                                          D Offline
                                          DTR+NSR
                                          wrote on last edited by
                                          #81

                                          @spookdog @spookdog a heat seizure is caused by the piston expanding to much/fast. From a lean mixture burning to hot. The piston basically becomes to big for the bore it's running in, and seizes. The fuel in a richer mixture actually takes heat from the piston crown. Lean mixture is backed up by the detonation you've seen on your piston.

                                          S 1 Reply Last reply
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