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DT125R FORUM

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Seized Engine

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  • CalumC Offline
    CalumC Offline
    Calum
    wrote on last edited by
    #4

    Genuine/Athena/Vertex seem to be the ones to go for. The cheap pattern ones are okay for (probably) for general gaskets, but the head must be one of the above.

    Always Originate, Never Pirate!

    1 Reply Last reply
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    • HOTSHOT IIIH Offline
      HOTSHOT IIIH Offline
      HOTSHOT III
      wrote on last edited by
      #5

      @GiannisT What @Calum said, also if your bike is an early DTR (i.e pre-'99) with the original Autolube pump, Yambits sell a rebuild kit for this which would be preferable to getting a used oil pump. You can still get the shims from Fowlers to adjust the flow rate/stroke (I think it the Yamaha or Haynes manual has a figure). Also early bikes have a mechanism inside the throttle cable splitter box which automatically balances the carb and oil pump at all throttle openings; the OEM cable is expensive but those 12 quid pattern throttle cables are responsible for a lot of DTR engine meltdowns. Get a cable oiler if you do a Yambits order (£5) and lube with Comma Spray Grease.

      G 1 Reply Last reply
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      • G GiannisT

        So I bought a piece of poo of a DTR from a friend for dirt cheap BUT with a seized motor. He told me the engine seized on him once, he had it rebored and fitted with a new piston, rings etc and he started running (poorly ratioed) premix since he suspected a faulty oil pump. A couple of months later, while riding, the engine shut off while idling at a red light and from that point on the motor has once again been seized. As a noobie going into my first 2-stroke rebuild, (assuming theres no crankshaft play) apart from dealing with re-reboring,piston,rings,seals etc and replacing the oil pump, is there anything else that should be obviously checked and could be the root of the problem? Any and all help is appreciated! thanks lads

        S Offline
        S Offline
        SpookDog
        wrote on last edited by SpookDog
        #6

        @GiannisT
        Hey bud! Wicked bike to learn mechanics on…
        What year is it? Also where are you based?…

        There’s no reason an engine should seize up ticking over at the lights. It’s more likely a ‘forgot to insert oil’ situation. Especially if it’s still locked up tight (is it still locked up?) Heat seizures usually free off after the engine has cooled down a bit. If this is the case I’d check the crank bearings are running smooth without any rumble/grumbling…

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        • HOTSHOT IIIH HOTSHOT III

          @GiannisT What @Calum said, also if your bike is an early DTR (i.e pre-'99) with the original Autolube pump, Yambits sell a rebuild kit for this which would be preferable to getting a used oil pump. You can still get the shims from Fowlers to adjust the flow rate/stroke (I think it the Yamaha or Haynes manual has a figure). Also early bikes have a mechanism inside the throttle cable splitter box which automatically balances the carb and oil pump at all throttle openings; the OEM cable is expensive but those 12 quid pattern throttle cables are responsible for a lot of DTR engine meltdowns. Get a cable oiler if you do a Yambits order (£5) and lube with Comma Spray Grease.

          G Offline
          G Offline
          GiannisT
          wrote on last edited by
          #7

          @HOTSHOT-III ok first of, thanks for the help. My bike is a 93 model (or 96 i always get confused) so i think i will go about repairing the pump as you suggested. Im not based in the UK so ive no clue what fowlers is but from what i saw yambits provides all the shims i would need.
          Now on to that throttle cable splitter box mechanism thingy...please help me understand what is and what needs to be done. Im new to the platform and got me bare confused since ive no idea what youre talking about. also if there are parts that i should opt for or definitely avoid i would appreciate some suggestions.

          HOTSHOT IIIH 1 Reply Last reply
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          • S SpookDog

            @GiannisT
            Hey bud! Wicked bike to learn mechanics on…
            What year is it? Also where are you based?…

            There’s no reason an engine should seize up ticking over at the lights. It’s more likely a ‘forgot to insert oil’ situation. Especially if it’s still locked up tight (is it still locked up?) Heat seizures usually free off after the engine has cooled down a bit. If this is the case I’d check the crank bearings are running smooth without any rumble/grumbling…

            G Offline
            G Offline
            GiannisT
            wrote on last edited by
            #8

            @SpookDog hello mate, the bike is either a 93 or a 96 dtr and I find myself based is Greece. I dont know how the bike locked up or how bad the damage really is since i havent dove into it yet; im going off what my friend told me. The bike has had a fair amount of time to cool down (in fact it has sat for about a year) and I fear greatly finding coolant into my cylinder and having to tear the whole thing apart to deal with that rusty mess. im being hopeful for the moment and trying to figure out how i would deal with the best case scenario. As soon i get into it (should be during the weekend) i ll be running back here asking for additional help.

            S 1 Reply Last reply
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            • G GiannisT

              @SpookDog hello mate, the bike is either a 93 or a 96 dtr and I find myself based is Greece. I dont know how the bike locked up or how bad the damage really is since i havent dove into it yet; im going off what my friend told me. The bike has had a fair amount of time to cool down (in fact it has sat for about a year) and I fear greatly finding coolant into my cylinder and having to tear the whole thing apart to deal with that rusty mess. im being hopeful for the moment and trying to figure out how i would deal with the best case scenario. As soon i get into it (should be during the weekend) i ll be running back here asking for additional help.

              S Offline
              S Offline
              SpookDog
              wrote on last edited by
              #9

              @GiannisT

              Hi bud! I think @MadGyver is based in Greece as well.
              Realistically until you pull off the top end you’re not going to be able to work anything out.
              Any chance of some pics of the bike?

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              • G GiannisT

                @HOTSHOT-III ok first of, thanks for the help. My bike is a 93 model (or 96 i always get confused) so i think i will go about repairing the pump as you suggested. Im not based in the UK so ive no clue what fowlers is but from what i saw yambits provides all the shims i would need.
                Now on to that throttle cable splitter box mechanism thingy...please help me understand what is and what needs to be done. Im new to the platform and got me bare confused since ive no idea what youre talking about. also if there are parts that i should opt for or definitely avoid i would appreciate some suggestions.

                HOTSHOT IIIH Offline
                HOTSHOT IIIH Offline
                HOTSHOT III
                wrote on last edited by
                #10

                @GiannisT No worries bud. Fowlers is a big dealership in the UK where a lot of people order their Yamaha parts from but if you're in Europe, CMSNL and Yamaha Amsterdam are also very good:

                https://www.cmsnl.com/

                https://www.yamahacenteramsterdam.nl/en/

                And Yamaha France parts lookup is the most accurate I've ever used, you can input your VIN number and it should find your bike:

                https://www.yamaha-motor.eu/fr/fr/service-support/parts-catalogue/

                The throttle cable splitter box is really simple, if you buy a genuine Yamaha cable by part number it comes assembled and complete and the balance mechanism is inside the box halfway down the cable where the two cables go to the carb and oil pump. You don't have to do anything to it apart from lubing it like any other cable, like I say it automatically balances the carb and oil pump at all throttle openings which is why genuine throttle cables for early bikes like yours don't have an adjuster on the oil pump cable. The TZR125 never had this, it was only the DTR as far as I know. Here's an explanation and pic from the Haynes manual:

                alt text

                alt text

                G 1 Reply Last reply
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                • MadGyverM Offline
                  MadGyverM Offline
                  MadGyver
                  wrote on last edited by
                  #11

                  @GiannisT Hey bud,if you want parts get them from Yamaha Nikolakopoulos,they helped me a lot with my rebuild and get me everything, Even the most weird parts that I needed,it was a very worn abused bike.

                  I need my tools and a pile of junk.....

                  G 1 Reply Last reply
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                  • HOTSHOT IIIH HOTSHOT III

                    @GiannisT No worries bud. Fowlers is a big dealership in the UK where a lot of people order their Yamaha parts from but if you're in Europe, CMSNL and Yamaha Amsterdam are also very good:

                    https://www.cmsnl.com/

                    https://www.yamahacenteramsterdam.nl/en/

                    And Yamaha France parts lookup is the most accurate I've ever used, you can input your VIN number and it should find your bike:

                    https://www.yamaha-motor.eu/fr/fr/service-support/parts-catalogue/

                    The throttle cable splitter box is really simple, if you buy a genuine Yamaha cable by part number it comes assembled and complete and the balance mechanism is inside the box halfway down the cable where the two cables go to the carb and oil pump. You don't have to do anything to it apart from lubing it like any other cable, like I say it automatically balances the carb and oil pump at all throttle openings which is why genuine throttle cables for early bikes like yours don't have an adjuster on the oil pump cable. The TZR125 never had this, it was only the DTR as far as I know. Here's an explanation and pic from the Haynes manual:

                    alt text

                    alt text

                    G Offline
                    G Offline
                    GiannisT
                    wrote on last edited by
                    #12

                    @HOTSHOT-III ok thats plently comprehensive. I think i know what im looking for but ill be back for follow-ups if i get stuck anywhere. Thanks again

                    1 Reply Last reply
                    1
                    • MadGyverM MadGyver

                      @GiannisT Hey bud,if you want parts get them from Yamaha Nikolakopoulos,they helped me a lot with my rebuild and get me everything, Even the most weird parts that I needed,it was a very worn abused bike.

                      G Offline
                      G Offline
                      GiannisT
                      wrote on last edited by
                      #13

                      @MadGyver my guy! you just made my life a whoooole lot easier. Na sai kala!

                      1 Reply Last reply
                      0
                      • MadGyverM Offline
                        MadGyverM Offline
                        MadGyver
                        wrote on last edited by
                        #14

                        @GiannisT No worries bud,if I can help you with parts in Greece or knowledge I will tell you.
                        Τίποτα φίλε.

                        I need my tools and a pile of junk.....

                        1 Reply Last reply
                        0
                        • G Offline
                          G Offline
                          GiannisT
                          wrote on last edited by GiannisT
                          #15

                          Well i finally had the time to dive into it yesterday. pulled the engine out (which was a much bigger pain than anticipated) and dove into the top end. Needless to say, this is going to be a tricky one. Theres a huge chunk missing from the left side of my piston, plenty of coolant in the bottom end and the connecting rod is rattling left and right like a mf. Also it appears a metal headgasket was used(?). Since i wasnt mentally prepared to dive into the bottom end and fully rebuild this thing I am in grave need of all the help and advice i can get. Cheers

                          (also ive been trying to upload/link pictures and a video for like 20' now and i cant seem to figure it out)

                          S HOTSHOT IIIH 2 Replies Last reply
                          0
                          • G GiannisT

                            Well i finally had the time to dive into it yesterday. pulled the engine out (which was a much bigger pain than anticipated) and dove into the top end. Needless to say, this is going to be a tricky one. Theres a huge chunk missing from the left side of my piston, plenty of coolant in the bottom end and the connecting rod is rattling left and right like a mf. Also it appears a metal headgasket was used(?). Since i wasnt mentally prepared to dive into the bottom end and fully rebuild this thing I am in grave need of all the help and advice i can get. Cheers

                            (also ive been trying to upload/link pictures and a video for like 20' now and i cant seem to figure it out)

                            S Offline
                            S Offline
                            SpookDog
                            wrote on last edited by SpookDog
                            #16

                            @GiannisT

                            Hey bud! Metal head gasket is standard. Con rod side to side movement is normal, they are never fixed ‘in place’. It’s purely the up and down play you don’t want. It would of been making a knocking noise before if it was bad.

                            I’d get someone with previous experience to have a look at the crank and bearings. If they’re ok just flush out the crank case and rebore and new piston that puppy!…

                            Host the pics on Imgur then copy the link.
                            On the toolbar (3rd from the SORRY! right) there’s an oblong box with what looks like a mountain with a moon In it. Click on that and paste your link in…

                            G 1 Reply Last reply
                            0
                            • G GiannisT

                              Well i finally had the time to dive into it yesterday. pulled the engine out (which was a much bigger pain than anticipated) and dove into the top end. Needless to say, this is going to be a tricky one. Theres a huge chunk missing from the left side of my piston, plenty of coolant in the bottom end and the connecting rod is rattling left and right like a mf. Also it appears a metal headgasket was used(?). Since i wasnt mentally prepared to dive into the bottom end and fully rebuild this thing I am in grave need of all the help and advice i can get. Cheers

                              (also ive been trying to upload/link pictures and a video for like 20' now and i cant seem to figure it out)

                              HOTSHOT IIIH Offline
                              HOTSHOT IIIH Offline
                              HOTSHOT III
                              wrote on last edited by HOTSHOT III
                              #17

                              @GiannisT If you do end up having to split the crankcases, here's the link to the crankcase splitter/crankshaft puller combo I used, these are made in the same factory as the "Tusk" branded version sold by Rocky Mountain ATVMC in the US but a lot cheaper:

                              https://uk.vevor.com/crankcase-splitter-separator-c_11501/crank-case-splitter-separator-puller-installer-automotive-dirt-bike-supplies-p_010929606602?adp=gmc&utm_source=google&utm_medium=cpc&utm_id=20497631423&utm_term=&gad_source=1&gclid=CjwKCAiAlJKuBhAdEiwAnZb7lWFwnMSlDdb5uSzPdY8J-nY9RNRX31UW8116ea7LeXDXBSEerq6P2hoCUrIQAvD_BwE

                              This is the adapter I had made for pulling the crankshaft back into the left main bearing to avoid transmitting a side load through the bearing (which will shorten its life). I had this made up at a local machine shop, you can see how it works, also check out the comments on this YouTube vid, lots of people saying the same thing:

                              https://www.youtube.com/watch?v=p0LK30KVWJg&t=1s

                              alt text

                              alt text

                              alt text

                              alt text

                              alt text

                              alt text

                              1 Reply Last reply
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                              • S SpookDog

                                @GiannisT

                                Hey bud! Metal head gasket is standard. Con rod side to side movement is normal, they are never fixed ‘in place’. It’s purely the up and down play you don’t want. It would of been making a knocking noise before if it was bad.

                                I’d get someone with previous experience to have a look at the crank and bearings. If they’re ok just flush out the crank case and rebore and new piston that puppy!…

                                Host the pics on Imgur then copy the link.
                                On the toolbar (3rd from the SORRY! right) there’s an oblong box with what looks like a mountain with a moon In it. Click on that and paste your link in…

                                G Offline
                                G Offline
                                GiannisT
                                wrote on last edited by
                                #18

                                @SpookDog some side movement may be normal but i can’t possibly believe what im looking at is okay. Give this a look and give the video a listen: alt text

                                S 1 Reply Last reply
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                                • G GiannisT

                                  @SpookDog some side movement may be normal but i can’t possibly believe what im looking at is okay. Give this a look and give the video a listen: alt text

                                  S Offline
                                  S Offline
                                  SpookDog
                                  wrote on last edited by SpookDog
                                  #19

                                  @GiannisT

                                  Bud! Do it without the piston on. It does look excessive but the piston noise and camera wobble doesn’t help…

                                  1 Reply Last reply
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                                  • MadGyverM Offline
                                    MadGyverM Offline
                                    MadGyver
                                    wrote on last edited by
                                    #20

                                    Suggestion.
                                    If you have never open an engine before see some extended video's rebuilding DTR engine. Take notes,ask and have a lot of patience. It's an engine that tou lay hands firts time.
                                    I've opened my engine 6 times during the rebuild and had manufactured all the tools at the 3rd time. Had seen many video's.and read almost all this forum and the old archived one.

                                    I need my tools and a pile of junk.....

                                    1 Reply Last reply
                                    0
                                    • CalumC Offline
                                      CalumC Offline
                                      Calum
                                      wrote on last edited by
                                      #21

                                      That engine loos F@CKED lol.

                                      The cylinder head is shot, the piston is half missing.

                                      The piston is supposed to have float. What people are referring to is some minor "Big End" float on the crank shaft, not the piston float on the gudgeon pin. I highly doubt that engine seized on tickover, looks like piston "Death Ash", indicating that's been running lean for some time. The piston skirt is damaged and therefore it's probably gone into the bottom end.

                                      Always Originate, Never Pirate!

                                      G 1 Reply Last reply
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                                      • CalumC Calum

                                        That engine loos F@CKED lol.

                                        The cylinder head is shot, the piston is half missing.

                                        The piston is supposed to have float. What people are referring to is some minor "Big End" float on the crank shaft, not the piston float on the gudgeon pin. I highly doubt that engine seized on tickover, looks like piston "Death Ash", indicating that's been running lean for some time. The piston skirt is damaged and therefore it's probably gone into the bottom end.

                                        G Offline
                                        G Offline
                                        GiannisT
                                        wrote on last edited by
                                        #22

                                        @Calum how would you go about dealing with this? Is there a smarter/better way of going about it than just tearing the engine down to bolts and going from there? Also while we’re at it, what should be done to the head besides it getting skimmed?

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                                        • CalumC Offline
                                          CalumC Offline
                                          Calum
                                          wrote on last edited by
                                          #23

                                          @GiannisT The smart thing to do would be to tear it down and inspect/renew where appropriate. There is no shortcuts, one way or the other that engine is coming apart. If the swarf hasn't contaminated the main bearings it'll no doubt have damaged the big end bearing. Anything short cut you do will likely cause further harm and stress to other components causing bigger, more expensive, problems in the long run. That bike didn't die on tickover, going by the extent of the damage to that piston/head.

                                          The head needs throwing in the bin, it's trashed. You might be able to get a tuner to alter the squishband and remove the detonation/debris marks from the head, but as it stands it's a glorified paper weight.

                                          The problem with running damaged heads such as that, is that it encourages detonation, even if the jetting appears to be correct. In other words, it's just a shortcut to a blown engine, doubly frustrating when it's freshly built.

                                          My advice, don't scrimp on critical components, it'll just come back to bite you.

                                          You could spit the cases and inspect the components for wear. If all is in order then you may not need to renew (although I would anyway).

                                          You could just inspect it in situ and see if the float is okay and if the big end bearing is damaged by checking for play. No way to tell about the mains or crankcase seals without tearing it apart. If debris has contaminated the seals then it will never idle/run right.

                                          Always Originate, Never Pirate!

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