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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 Hhmm interesting. I mean the later models had the exact same engine but with 210 main jet which is odd. And even DEP themselves say no need to up jet with their performance exhaust.

    I noticed when I went to a Wossner Forged Piston that it needed up jetting however.

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    SpookDog
    wrote on last edited by SpookDog
    #116

    @Calum

    I’ve got two of the 99~ carbs with 240 main and.25 pilot and I know there are at least two other variations. Different jetting and valve cutaway, ect. As long as they make a 14/86 ratio of fuel mix it should be sweet! I can only guess at different emissions laws at different times...
    Then there’s the TZR 28mm Mikuni flat slides!...

    Truth is that it’s a fecking mystery to me that I’m still trying to suss out 😜 ...

    I’ve never understood the upjet a new exhaust mentality. Why would it want a richer mixture? Then again, a bigger jet making your bike faster was the first ‘old boy~racers tale’ I ever heard! Maybe it’s just endured?...

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    • S SpookDog

      @Calum

      I’ve got two of the 99~ carbs with 240 main and.25 pilot and I know there are at least two other variations. Different jetting and valve cutaway, ect. As long as they make a 14/86 ratio of fuel mix it should be sweet! I can only guess at different emissions laws at different times...
      Then there’s the TZR 28mm Mikuni flat slides!...

      Truth is that it’s a fecking mystery to me that I’m still trying to suss out 😜 ...

      I’ve never understood the upjet a new exhaust mentality. Why would it want a richer mixture? Then again, a bigger jet making your bike faster was the first ‘old boy~racers tale’ I ever heard! Maybe it’s just endured?...

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      SpookDog
      wrote on last edited by
      #117

      Still getting sputters at certain times! This is really starting to bug the bejesus out of me now. It can only be a few things to my mind.
      1: Crap in carb (my tank is really rusty inside)
      2: fuel starvation (I have a loop of fuel pipe that is constantly full of air a few inches long)
      3: a random ignition bug...

      1: I have another tank that is pristine inside but been sanded down to bare metal and left to rust. I’ve Harpic’d the rust and am waiting to see what happens...
      2: The excess pipe is there cause I need a fuel filter on because of the tank crap. So I’m gonna fit the new tank without the clunky filter...
      3: I got a new Iridium plug and cap to fit, tho I don’t believe it’s an electrical problem...
      I’ve also got a pristine late carb to put on while I’m at it. The floats haven’t been played with and it is so clean inside it’s almost unreal!...

      Fingers crossed 🤞

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      • S SpookDog

        Still getting sputters at certain times! This is really starting to bug the bejesus out of me now. It can only be a few things to my mind.
        1: Crap in carb (my tank is really rusty inside)
        2: fuel starvation (I have a loop of fuel pipe that is constantly full of air a few inches long)
        3: a random ignition bug...

        1: I have another tank that is pristine inside but been sanded down to bare metal and left to rust. I’ve Harpic’d the rust and am waiting to see what happens...
        2: The excess pipe is there cause I need a fuel filter on because of the tank crap. So I’m gonna fit the new tank without the clunky filter...
        3: I got a new Iridium plug and cap to fit, tho I don’t believe it’s an electrical problem...
        I’ve also got a pristine late carb to put on while I’m at it. The floats haven’t been played with and it is so clean inside it’s almost unreal!...

        Fingers crossed 🤞

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        mhbikesnbits
        wrote on last edited by
        #118

        @SpookDog the first two could be the issue to me the loop and and rust. Would try and sort them ASAP, how’s the piston in the top end also is it likely to be good

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        • M mhbikesnbits

          @SpookDog the first two could be the issue to me the loop and and rust. Would try and sort them ASAP, how’s the piston in the top end also is it likely to be good

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          SpookDog
          wrote on last edited by
          #119

          @mhbikesnbits

          I had a partial seizure a while ago. It didn’t even cut out the engine I caught it so quick. The bore looks ok apart from a couple bright lines at the usual points around the gudgeon pin. I haven’t removed the barrel to check the piston yet. I was gonna wait and get a new piston and hone it myself...

          I don’t think it’s the piston though just because of the nature of it. Back off from the sputter and it’s fine again after, also there’s just no rhyme or reason to when it happens...

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          • S SpookDog

            @mhbikesnbits

            I had a partial seizure a while ago. It didn’t even cut out the engine I caught it so quick. The bore looks ok apart from a couple bright lines at the usual points around the gudgeon pin. I haven’t removed the barrel to check the piston yet. I was gonna wait and get a new piston and hone it myself...

            I don’t think it’s the piston though just because of the nature of it. Back off from the sputter and it’s fine again after, also there’s just no rhyme or reason to when it happens...

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            mhbikesnbits
            wrote on last edited by
            #120

            @SpookDog how’s the compression, I can remember my dtx sputtered before my top end went

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            • M mhbikesnbits

              @SpookDog how’s the compression, I can remember my dtx sputtered before my top end went

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              SpookDog
              wrote on last edited by SpookDog
              #121

              @mhbikesnbits

              It’s good. I really think it’s the air gap in the fuel pipe. If the motor is drinking it faster than it’s getting in, it sputters. It’s about 5 or 6 inches of airlocked pipe...
              I can’t do pics at the moment cause my phone dies if you unplug it...

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              • S SpookDog

                @mhbikesnbits

                It’s good. I really think it’s the air gap in the fuel pipe. If the motor is drinking it faster than it’s getting in, it sputters. It’s about 5 or 6 inches of airlocked pipe...
                I can’t do pics at the moment cause my phone dies if you unplug it...

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                SpookDog
                wrote on last edited by
                #122

                Harpic is actually the Dogs Bollox at dissolving rust! As long as you keep it ‘saturated’ and don’t let it dry out it keeps on dissolving. Top Tip whoever it was who mentioned it! The outside of my second hand tank is now rust free after the previous owner sanded it down to bare metal and left it...

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                • S SpookDog

                  Harpic is actually the Dogs Bollox at dissolving rust! As long as you keep it ‘saturated’ and don’t let it dry out it keeps on dissolving. Top Tip whoever it was who mentioned it! The outside of my second hand tank is now rust free after the previous owner sanded it down to bare metal and left it...

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                  SpookDog
                  wrote on last edited by
                  #123

                  @SpookDog

                  Hi me! A lot of this is for future reference so I can remember the timeline until I can finally chase the bugs out of my bike..

                  After putting a couple tanks of petrol through the new tank I finally got it to run sweet and true with smooth power delivery. No fuel ‘lag’ problems with the new pipe routing without the airlock...

                  Head gasket is leaking again though 🙄 only changed it in March and can’t blame this one on the lean jetting. I gotta stop buying cheap Athena gaskets off of fleabay? Try again with a Vertex gasket...

                  Check if it’s the same spot as well...

                  CalumC 1 Reply Last reply
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                  • S SpookDog

                    @SpookDog

                    Hi me! A lot of this is for future reference so I can remember the timeline until I can finally chase the bugs out of my bike..

                    After putting a couple tanks of petrol through the new tank I finally got it to run sweet and true with smooth power delivery. No fuel ‘lag’ problems with the new pipe routing without the airlock...

                    Head gasket is leaking again though 🙄 only changed it in March and can’t blame this one on the lean jetting. I gotta stop buying cheap Athena gaskets off of fleabay? Try again with a Vertex gasket...

                    Check if it’s the same spot as well...

                    CalumC Offline
                    CalumC Offline
                    Calum
                    wrote on last edited by
                    #124

                    @SpookDog Never had a problem with Athena gaskets they're quality parts.

                    I'd say something is wrong with the engine if you're having problems.

                    That said, I'd only get my gaskets from PJME or other reputable sources, not randomers off of eBay.

                    Always Originate, Never Pirate!

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                    • CalumC Calum

                      @SpookDog Never had a problem with Athena gaskets they're quality parts.

                      I'd say something is wrong with the engine if you're having problems.

                      That said, I'd only get my gaskets from PJME or other reputable sources, not randomers off of eBay.

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                      SpookDog
                      wrote on last edited by SpookDog
                      #125

                      @Calum

                      Oh yeah, absolutely. I’m not knocking Athena as a product. They’re the best affordable option. I just don’t know the history of the fleabay ones. I don’t know if the coating on the aluminium gasket has a shelf life, maybe? They might of been exposed to high or low temps?
                      I wish I could find fault in the way I’ve been doing the top end rebuilds but I can’t 😐

                      Sure I’ll suss it in the long run. Maybe you’re only supposed to spread the peanut butter on one side of the gasket? 🙂 ...

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                      • S SpookDog

                        @Calum

                        Oh yeah, absolutely. I’m not knocking Athena as a product. They’re the best affordable option. I just don’t know the history of the fleabay ones. I don’t know if the coating on the aluminium gasket has a shelf life, maybe? They might of been exposed to high or low temps?
                        I wish I could find fault in the way I’ve been doing the top end rebuilds but I can’t 😐

                        Sure I’ll suss it in the long run. Maybe you’re only supposed to spread the peanut butter on one side of the gasket? 🙂 ...

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                        SpookDog
                        wrote on last edited by SpookDog
                        #126

                        @SpookDog
                        IIRC:
                        Since I put a new barrel & piston & head on with new gasket (last August) it lasted 7 months until the head gasket went in March. I blame road salt corrosion on the head studs for that one.
                        This one lasted a month with new gasket, relapped head & barrel and Yamaha dome nuts and washers. I’m hoping that this time was either gasket fault or my fault fitting. I even lifted the engine out so I could get to it with the torque wrench nice and evenly. Cleaned and degreased all surfaces with Wurth degreasant. So I’m gonna have to be extra surgical next time 😜

                        CalumC 1 Reply Last reply
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                        • S SpookDog

                          @SpookDog
                          IIRC:
                          Since I put a new barrel & piston & head on with new gasket (last August) it lasted 7 months until the head gasket went in March. I blame road salt corrosion on the head studs for that one.
                          This one lasted a month with new gasket, relapped head & barrel and Yamaha dome nuts and washers. I’m hoping that this time was either gasket fault or my fault fitting. I even lifted the engine out so I could get to it with the torque wrench nice and evenly. Cleaned and degreased all surfaces with Wurth degreasant. So I’m gonna have to be extra surgical next time 😜

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #127

                          @SpookDog WTF - There has GOT to be something wrong with your engine. There just has to be!

                          I've never had any problems with head gaskets except the cheap white ones you get off of fleabay. I've had some horrible engines in my time too and they were absolutely fine.

                          So this is very odd.

                          Always Originate, Never Pirate!

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                          • CalumC Calum

                            @SpookDog WTF - There has GOT to be something wrong with your engine. There just has to be!

                            I've never had any problems with head gaskets except the cheap white ones you get off of fleabay. I've had some horrible engines in my time too and they were absolutely fine.

                            So this is very odd.

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                            SpookDog
                            wrote on last edited by
                            #128

                            @Calum

                            I know, I don’t even ride aggressively. This is a new barrel and head since my ‘old’ problems. The first gasket on this top end lasted 7 months and rust got into the studs and nuts, so that’s acceptable. This one has lasted 6 weeks. I’m hoping it was a bad gasket (I’ve had a scratched one before) or ahem user error 🙄 We’ll see when I can be bothered to strip the top end again...

                            I don’t seem to have much luck though, that and a painfully slow learning curve are working out worse than a Gypsy Curse! 👻

                            I will get there thought. I’ve got a 93 4HW TZR project to get my teeth into yet. Can’t find any info on that thing...

                            CalumC M 2 Replies Last reply
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                            • S SpookDog

                              @Calum

                              I know, I don’t even ride aggressively. This is a new barrel and head since my ‘old’ problems. The first gasket on this top end lasted 7 months and rust got into the studs and nuts, so that’s acceptable. This one has lasted 6 weeks. I’m hoping it was a bad gasket (I’ve had a scratched one before) or ahem user error 🙄 We’ll see when I can be bothered to strip the top end again...

                              I don’t seem to have much luck though, that and a painfully slow learning curve are working out worse than a Gypsy Curse! 👻

                              I will get there thought. I’ve got a 93 4HW TZR project to get my teeth into yet. Can’t find any info on that thing...

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #129

                              @SpookDog Definitely not putting the gasket on upside down?

                              You're torquing the head up evenly in a star pattern up to around 22nm? Are you using grease in the bolts as this will impact the reading you get from the torque. Greased bolts torque higher than ungreased?

                              Sorry if this is very basic but I'm literally baffled!

                              Always Originate, Never Pirate!

                              S 2 Replies Last reply
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                              • S SpookDog

                                @Calum

                                I know, I don’t even ride aggressively. This is a new barrel and head since my ‘old’ problems. The first gasket on this top end lasted 7 months and rust got into the studs and nuts, so that’s acceptable. This one has lasted 6 weeks. I’m hoping it was a bad gasket (I’ve had a scratched one before) or ahem user error 🙄 We’ll see when I can be bothered to strip the top end again...

                                I don’t seem to have much luck though, that and a painfully slow learning curve are working out worse than a Gypsy Curse! 👻

                                I will get there thought. I’ve got a 93 4HW TZR project to get my teeth into yet. Can’t find any info on that thing...

                                M Offline
                                M Offline
                                mhbikesnbits
                                wrote on last edited by
                                #130

                                @SpookDog did you take them head off for any reason within them 6 weeks as once you’ve tightened the head once you cant take it off again without needing a new gasket or it doesn’t seal properly, only other thing is check the torque of the bolt again once the engines heated

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                                • CalumC Calum

                                  @SpookDog Definitely not putting the gasket on upside down?

                                  You're torquing the head up evenly in a star pattern up to around 22nm? Are you using grease in the bolts as this will impact the reading you get from the torque. Greased bolts torque higher than ungreased?

                                  Sorry if this is very basic but I'm literally baffled!

                                  S Offline
                                  S Offline
                                  SpookDog
                                  wrote on last edited by SpookDog
                                  #131

                                  @Calum

                                  Up side up,
                                  Using a 1/4 inch drive torque wrench (and lifting the engine up to get at all the nuts evenly and unobstructed)
                                  Studs dry and wire brushed clean.
                                  I clean the top of the barrel and the head by gently lapping them with (180 grit I think) wet & dry on glass, then look for any high or low points with a steel rule.
                                  I clean everything down with solvent, except the gasket which I use straight out of the plastic wrap.

                                  I seriously don’t take offence. It’s a mystery to me what I’m doing wrong, but I’ll get there eventually! It only took me 18 months to work out the jetting! 😜

                                  @MH-Bikes-N-Bits

                                  I haven’t loosened or removed the head at all. I haven’t thought about retorquing the head after running just because it’s such a pain in the ass to get at the nuts ‘in frame’
                                  I might have to consider it though. Does anyone else re-torque after first run?...

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                                  • CalumC Calum

                                    @SpookDog Definitely not putting the gasket on upside down?

                                    You're torquing the head up evenly in a star pattern up to around 22nm? Are you using grease in the bolts as this will impact the reading you get from the torque. Greased bolts torque higher than ungreased?

                                    Sorry if this is very basic but I'm literally baffled!

                                    S Offline
                                    S Offline
                                    SpookDog
                                    wrote on last edited by
                                    #132

                                    @Calum

                                    Actually, I think I’ve been tightening them up to 28 kgf-m
                                    I’ll have to double check before I loose the nuts off. If it’s over tightening I’ll kick myself!

                                    CalumC 1 Reply Last reply
                                    0
                                    • S SpookDog

                                      @Calum

                                      Up side up,
                                      Using a 1/4 inch drive torque wrench (and lifting the engine up to get at all the nuts evenly and unobstructed)
                                      Studs dry and wire brushed clean.
                                      I clean the top of the barrel and the head by gently lapping them with (180 grit I think) wet & dry on glass, then look for any high or low points with a steel rule.
                                      I clean everything down with solvent, except the gasket which I use straight out of the plastic wrap.

                                      I seriously don’t take offence. It’s a mystery to me what I’m doing wrong, but I’ll get there eventually! It only took me 18 months to work out the jetting! 😜

                                      @MH-Bikes-N-Bits

                                      I haven’t loosened or removed the head at all. I haven’t thought about retorquing the head after running just because it’s such a pain in the ass to get at the nuts ‘in frame’
                                      I might have to consider it though. Does anyone else re-torque after first run?...

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                                      M Offline
                                      mhbikesnbits
                                      wrote on last edited by
                                      #133

                                      @SpookDog I mean with expansion sometimes things can work loose, people heat things up when they can’t get it loose, I will probably recheck mine. I’m pretty sure when I changed my sump gasket on my landrover the other month it said on the guide check the torque of the bolts once the engines warmed up

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                                      • S SpookDog

                                        @Calum

                                        Actually, I think I’ve been tightening them up to 28 kgf-m
                                        I’ll have to double check before I loose the nuts off. If it’s over tightening I’ll kick myself!

                                        CalumC Offline
                                        CalumC Offline
                                        Calum
                                        wrote on last edited by
                                        #134

                                        @SpookDog I've retorqued them on my DT as it was leaking coolant out the side 🤣 I thought it said 12nm torque which was far too low. Still head gasket was fine to retorque even though I'd done several trips to the shops on it.

                                        Always Originate, Never Pirate!

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                                        • CalumC Calum

                                          @SpookDog I've retorqued them on my DT as it was leaking coolant out the side 🤣 I thought it said 12nm torque which was far too low. Still head gasket was fine to retorque even though I'd done several trips to the shops on it.

                                          S Offline
                                          S Offline
                                          SpookDog
                                          wrote on last edited by
                                          #135

                                          @Calum
                                          That is well surprising! I’d of thought that once contaminated with coolant it’d be FUBAR

                                          CalumC 1 Reply Last reply
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