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DT125R FORUM

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  4. So Close!...

So Close!...

Scheduled Pinned Locked Moved DTR
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  • CalumC Calum

    @spookdog But that's what I'm saying, 2 smoke is enthusiasts. The youths are no longer interested in buying smokers. Maybe they never were, maybe people would just buy whatever was available and it just so happened to be that two strokes were the go to.

    My point still stands, youths aren't interested in smokers. It's now just an enthusiast thing.

    And Two Strokes still dominate the MX realm and they're making great strides with Two Strokes. Fuel Injection is now common place in the smoker scene. As well as AWD MX bikes 😛

    If you haven't checked out Cristinis AWD Motorcross bikes

    Two strokes are still very much here, but the demand is less because people don't actively buy them.

    https://www.christini.com/bikes/christini-awd-300

    alt text

    This one is carb but EFI is now common place for KTM, Husky and the like!

    If you haven't checked out Cristini's AWD then go take a look 😃 Sick as.

    alt text

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    SpookDog
    wrote on last edited by SpookDog
    #46

    Mine own creation!...

    alt text

    alt text

    It looks super bright (& a bit white) in the pic (or just ‘washed out), or it did in the original! but there is a reflector lense from one of those cheap stick on reflectors bonded over the red led. It’s actually no brighter than the tail light and kinda mellow. Beats carrying a spare bulb on long night rides...

    Got it wired in with the front led spots...

    alt text

    I call them dog lites 🐾

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    • S SpookDog

      Mine own creation!...

      alt text

      alt text

      It looks super bright (& a bit white) in the pic (or just ‘washed out), or it did in the original! but there is a reflector lense from one of those cheap stick on reflectors bonded over the red led. It’s actually no brighter than the tail light and kinda mellow. Beats carrying a spare bulb on long night rides...

      Got it wired in with the front led spots...

      alt text

      I call them dog lites 🐾

      S Offline
      S Offline
      SpookDog
      wrote on last edited by SpookDog
      #47

      alt text

      Blown Again! 🌬

      Above is my new Athena gasket. I should of checked it closer before fitting. I didn’t see the scratch cause it was black with the coating. So this time it’s on me (again!! 😳 )

      alt text

      You can see the leak path as a thin black line. The wetness in the head isn’t coolant, it’s unburnt oil (after a 70 mile ride!) Funny thing is the bike ran better after the head blew! The revs were crisp on pickup and really well ‘defined’. The rich mixture is another ongoing issue.

      This is the plug after the same journey.

      alt text

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      • S SpookDog

        alt text

        Blown Again! 🌬

        Above is my new Athena gasket. I should of checked it closer before fitting. I didn’t see the scratch cause it was black with the coating. So this time it’s on me (again!! 😳 )

        alt text

        You can see the leak path as a thin black line. The wetness in the head isn’t coolant, it’s unburnt oil (after a 70 mile ride!) Funny thing is the bike ran better after the head blew! The revs were crisp on pickup and really well ‘defined’. The rich mixture is another ongoing issue.

        This is the plug after the same journey.

        alt text

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        SpookDog
        wrote on last edited by SpookDog
        #48

        And for my next trick!

        This is within the last 70 miles...

        alt text

        What causes this? Overcompression? Overheating? It’s only disappearing below the spark plug so I don’t think it’s detonation, but I’m no expert...

        Help!!...

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        • S SpookDog

          And for my next trick!

          This is within the last 70 miles...

          alt text

          What causes this? Overcompression? Overheating? It’s only disappearing below the spark plug so I don’t think it’s detonation, but I’m no expert...

          Help!!...

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          DTR+NSR
          wrote on last edited by DTR+NSR
          #49

          @spookdog that is detonation/pre ignition damage! My dt was running 225psi compression before I lowered it and that suffered no detonation. Normally it's down to a lean mixture.

          What heat range spark plug are you running?
          Also heard of excess carbon build up causing detonation.

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          • S SpookDog

            Mine own creation!...

            alt text

            alt text

            It looks super bright (& a bit white) in the pic (or just ‘washed out), or it did in the original! but there is a reflector lense from one of those cheap stick on reflectors bonded over the red led. It’s actually no brighter than the tail light and kinda mellow. Beats carrying a spare bulb on long night rides...

            Got it wired in with the front led spots...

            alt text

            I call them dog lites 🐾

            E Offline
            E Offline
            EdFrearson
            wrote on last edited by
            #50

            @spookdog I really like this, that blue looks gorgeous 😍

            CalumC S 2 Replies Last reply
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            • E EdFrearson

              @spookdog I really like this, that blue looks gorgeous 😍

              CalumC Offline
              CalumC Offline
              Calum
              wrote on last edited by
              #51

              @edfrearson Endurance blue is definitely a favourite of mine.

              Always Originate, Never Pirate!

              1 Reply Last reply
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              • D DTR+NSR

                @spookdog that is detonation/pre ignition damage! My dt was running 225psi compression before I lowered it and that suffered no detonation. Normally it's down to a lean mixture.

                What heat range spark plug are you running?
                Also heard of excess carbon build up causing detonation.

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                SpookDog
                wrote on last edited by
                #52

                @dtr-nsr

                NGK-R BR9EVX

                I was told it was ‘the equivalent’...

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                • E EdFrearson

                  @spookdog I really like this, that blue looks gorgeous 😍

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                  S Offline
                  SpookDog
                  wrote on last edited by
                  #53

                  @edfrearson

                  Wasn’t my first choice! I also have every plastic panel (& tank) in mid/flat black.

                  1 Reply Last reply
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                  • S SpookDog

                    @dtr-nsr

                    NGK-R BR9EVX

                    I was told it was ‘the equivalent’...

                    D Offline
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                    DTR+NSR
                    wrote on last edited by
                    #54

                    @spookdog yeah they run a 9 heat range plug as standard. Could be a combination of raised compression and lean mixture. Can run lean running to much oil even.

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                    • D DTR+NSR

                      @spookdog yeah they run a 9 heat range plug as standard. Could be a combination of raised compression and lean mixture. Can run lean running to much oil even.

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                      SpookDog
                      wrote on last edited by SpookDog
                      #55

                      There’s a thread somewhere that has the volume of 3mb & 3bn heads, even has the volume of the dome on (a Makita, done it again!) Mitaka! piston iirc. I can’t find it for looking. Can anyone please help?...

                      I did a fluid test on the 3mb head I have fitted and it was more than my spare 3bn head! So I really need 3rd party measures...

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                      • S SpookDog

                        There’s a thread somewhere that has the volume of 3mb & 3bn heads, even has the volume of the dome on (a Makita, done it again!) Mitaka! piston iirc. I can’t find it for looking. Can anyone please help?...

                        I did a fluid test on the 3mb head I have fitted and it was more than my spare 3bn head! So I really need 3rd party measures...

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                        SpookDog
                        wrote on last edited by SpookDog
                        #56

                        Why am I only now hearing about o~ring heads! How long has this been viable tech?...
                        Am I missing out on anything else? Backwards compatible airflow metred injector inlets that run off of a simple lambda probe in the exhaust?! Perfect mixture all the time?!...

                        Ahhhhh 🤯

                        CalumC 1 Reply Last reply
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                        • S SpookDog

                          Why am I only now hearing about o~ring heads! How long has this been viable tech?...
                          Am I missing out on anything else? Backwards compatible airflow metred injector inlets that run off of a simple lambda probe in the exhaust?! Perfect mixture all the time?!...

                          Ahhhhh 🤯

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #57

                          @spookdog Aprilia RS 125 has O-Ring head gasket.

                          Always Originate, Never Pirate!

                          D 1 Reply Last reply
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                          • CalumC Calum

                            @spookdog Aprilia RS 125 has O-Ring head gasket.

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                            DTR+NSR
                            wrote on last edited by
                            #58

                            You'll raise the compression converting to o ring. It's not hard to get the fueling reasonably good with the stock carb. Only time I've suffered lean issues, it was the base gasket that had gone, leaking in air.

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                            • NottsbikerN Offline
                              NottsbikerN Offline
                              Nottsbiker
                              wrote on last edited by
                              #59

                              Apologies if this is a daft question as I'm late to the party, but if you're blowing head gaskets have you checked that the head and the cylinder surfaces are perfectly flat?

                              Could be an opportunity to take it off, remove the studs and lap them both flat again on a sheet of glass (or engineers table) to be 100% 🙂

                              Ignore me if you've already checked this issue 😉

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                              • NottsbikerN Nottsbiker

                                Apologies if this is a daft question as I'm late to the party, but if you're blowing head gaskets have you checked that the head and the cylinder surfaces are perfectly flat?

                                Could be an opportunity to take it off, remove the studs and lap them both flat again on a sheet of glass (or engineers table) to be 100% 🙂

                                Ignore me if you've already checked this issue 😉

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                                SpookDog
                                wrote on last edited by SpookDog
                                #60

                                @nottsbiker
                                No daft questions bud. I haven’t recorded all my nightmares. But yeah, I’ve removed the studs and cleaned , checked and lapped. The second and third time the head blew are down to me, once using a gasket that had already been fitted, again when I used a copper gasket without fully understanding the process and not using spray sealant. The final time there was a scratch in the gasket that I didn’t expect or spot.

                                I’ve fitted another new Athena gasket and torqued it properly. I’ve fitted a newly lapped 3bn head that’s tip top condition, and weirdly higher compression (12.5~13ml) than the 3mb I was using (14ml)...
                                The gasket blowing is only 1 issue I’m having. I have a black sooty plug, bogging down over 1/2 throttle and a nasty bog 1/4 throttle where the needle valve kicks in, that has been happening since I first got the bike. Oh and unburned oil in the chamber/ around plug. I’ve no idea what previous owners did to the carb. It was running on a 180 main jet though...
                                Every time I get somewhere another problem kicks in...

                                New Athena gasket torqued properly, I’ve disconnected the oil pump and gone premix. Rejetted the carb to standard and am going to take it from there. Square one again 🥴

                                S 1 Reply Last reply
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                                • S SpookDog

                                  @nottsbiker
                                  No daft questions bud. I haven’t recorded all my nightmares. But yeah, I’ve removed the studs and cleaned , checked and lapped. The second and third time the head blew are down to me, once using a gasket that had already been fitted, again when I used a copper gasket without fully understanding the process and not using spray sealant. The final time there was a scratch in the gasket that I didn’t expect or spot.

                                  I’ve fitted another new Athena gasket and torqued it properly. I’ve fitted a newly lapped 3bn head that’s tip top condition, and weirdly higher compression (12.5~13ml) than the 3mb I was using (14ml)...
                                  The gasket blowing is only 1 issue I’m having. I have a black sooty plug, bogging down over 1/2 throttle and a nasty bog 1/4 throttle where the needle valve kicks in, that has been happening since I first got the bike. Oh and unburned oil in the chamber/ around plug. I’ve no idea what previous owners did to the carb. It was running on a 180 main jet though...
                                  Every time I get somewhere another problem kicks in...

                                  New Athena gasket torqued properly, I’ve disconnected the oil pump and gone premix. Rejetted the carb to standard and am going to take it from there. Square one again 🥴

                                  S Offline
                                  S Offline
                                  SpookDog
                                  wrote on last edited by
                                  #61

                                  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?...

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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
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                                    • 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
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                                        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

                                        S 1 Reply Last reply
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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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