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DT125R FORUM

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Scheduled Pinned Locked Moved Engine
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  • BluestoesonnoseB Offline
    BluestoesonnoseB Offline
    Bluestoesonnose
    wrote on last edited by
    #13

    So these things are a direct swap on the DT cases

    2002 DT125R

    1 Reply Last reply
    0
    • BluestoesonnoseB Bluestoesonnose

      I'm confused by all the codes, remember I'm only learning about these engines atm

      CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by
      #14

      @Bluestoesonnose That's why I've linked you a video. The 4FU can be found on the European 4GW Belgarda TDR models.

      Google and Search should help you find what you're after.

      Yes they're direct swap.

      Always Originate, Never Pirate!

      1 Reply Last reply
      1
      • BluestoesonnoseB Offline
        BluestoesonnoseB Offline
        Bluestoesonnose
        wrote on last edited by Calum
        #15

        So this one

        292776003728

        https://www.ebay.co.uk/itm/YAMAHA-TZR-125-R-TZR125-R-4FU-USED-CYLINDER-BARREL/292776003728?hash=item442acf4890:g:kUUAAOSwjmFbQ1I1:rk:1:pf:0

        2002 DT125R

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        • BluestoesonnoseB Offline
          BluestoesonnoseB Offline
          Bluestoesonnose
          wrote on last edited by
          #16

          No idea what Rotax motor your on about though

          2002 DT125R

          CalumC 1 Reply Last reply
          0
          • BluestoesonnoseB Bluestoesonnose

            No idea what Rotax motor your on about though

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #17

            @Bluestoesonnose Rotax 122 barrel. £20
            https://www.ebay.co.uk/itm/Aprilia-RS125-Mitaka-Barrel-1991-2011-Rotax-122-And-123-RS-125-Spares-Or-Repair/192690108309?hash=item2cdd39b795:g:0UMAAOSwaIJbdEd3:rk:7:pf:0

            And the difference between that, and an SP barrel is negligible, yet you'll pay £500 with an SP barrel.

            Yes that one is the 4FU, but you will need the 4FU powervalve to suit.

            Always Originate, Never Pirate!

            1 Reply Last reply
            1
            • 2 Offline
              2 Offline
              2stroketerry
              wrote on last edited by
              #18

              Hi @Bluestoesonnose I have a spare 4FU00 barrel with the powervalve if you want will post some photos, just make an offer as no use to me as Athena 170 kit on my DT

              1 Reply Last reply
              0
              • BluestoesonnoseB Offline
                BluestoesonnoseB Offline
                Bluestoesonnose
                wrote on last edited by
                #19

                I could be interested as I've just discovered that my spare barrel is FUBAR as it's got a crack in it

                2002 DT125R

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                • 2 Offline
                  2 Offline
                  2stroketerry
                  wrote on last edited by
                  #20

                  Hi, photos of the 4FU barrel with powervalve fitted, you can see the bore is scored
                  so will need replating or reboring. Just make me an offer if any good to you.
                  0_1541473310223_1.jpg 0_1541473326104_2.jpg 0_1541473340116_3.jpg 0_1541473348850_4.jpg 0_1541473359147_5.jpg 0_1541473368648_6.jpg 0_1541473375261_7.jpg

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                  • BluestoesonnoseB Offline
                    BluestoesonnoseB Offline
                    Bluestoesonnose
                    wrote on last edited by
                    #21

                    Hi,
                    Looks good to me, no idea what the going rate is for one, ummm £75 posted?

                    2002 DT125R

                    BluestoesonnoseB 1 Reply Last reply
                    0
                    • 2 Offline
                      2 Offline
                      2stroketerry
                      wrote on last edited by
                      #22

                      Hi @Bluestoesonnose £85 posted ?

                      declanD 1 Reply Last reply
                      0
                      • 2 2stroketerry

                        Hi @Bluestoesonnose £85 posted ?

                        declanD Offline
                        declanD Offline
                        declan
                        wrote on last edited by
                        #23

                        @2stroketerry 85s a good price

                        1 Reply Last reply
                        0
                        • BluestoesonnoseB Bluestoesonnose

                          Hi,
                          Looks good to me, no idea what the going rate is for one, ummm £75 posted?

                          BluestoesonnoseB Offline
                          BluestoesonnoseB Offline
                          Bluestoesonnose
                          wrote on last edited by
                          #24

                          Hi, sorry to say I got offered one for £50 all in so I've bought that.

                          Thanks anyways

                          2002 DT125R

                          1 Reply Last reply
                          0
                          • 2 2stroketerry

                            To get DT to pull a lot harder should of fitted Athena 170 kit rather than a ported 125 barrel, have got a ported head and barrel off Mick and the 170 is miles better with the extra torque and being 20 stone the torque makes so much difference. My 170 is fully ported and revs to over 11,000 on a 2003 DT R using standard TM 28 carb with the powerjet blocked and standard air filter with snorkel on.
                            People who say ports are 3mm to low don't know anything about tuning as when mapped the ports and they are 125 ports and same hieght as 125 ports. The reason they don't rev past around 8,000 or so is because of the exhaust port width as on 2 strokes exhaust port width has to be a certain percent of the bore diameter, so going from 56mm bore to 65mm bore totaly screws up the engine. Exhaust port width limit is 73% of the bore diameter (measured straight across). So 56mm bore is 41mm and the 65mm bore can be opened up to 47mm.
                            Double check the pv cable setting on Athena kit as with holes lined up standard the powervalve is only 3/4 open, on mine set powervalve in cylinder flush then drilled a new 4mm hole in center of powervalve pully.
                            Engine tuning is all about everything working together and a combination of ports, compression, carb, ignition all perfectly matched. With the Athena kit most people run wrong plugs to suit it best like br9es or a br9eix irridium plug. The plugs to use on any ported DT are NGK B10EG non resister plugs along with 7mm HT lead copper core and a non resister plug cap.
                            The bottom end makes cruising more relaxed, and the extra top end means it'll now do a wheelie in 4th gear easy.

                            S Offline
                            S Offline
                            sprintall84
                            wrote on last edited by
                            #25

                            @2stroketerry what’s top speed you had out of your dt with the 170 kit on ?? Coz A few people saying there no good get a 4fu00 barrel and head ??

                            CalumC 1 Reply Last reply
                            0
                            • S sprintall84

                              @2stroketerry what’s top speed you had out of your dt with the 170 kit on ?? Coz A few people saying there no good get a 4fu00 barrel and head ??

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #26

                              @sprintall84 It's not necessary speed you benefit from, but more torque. So gear it appropriately you should be fine.

                              As a general whole, the Athena kit isn't brilliant. A 3MB00SP Barrel is what you want. But the price for those is astronomical.

                              4FU is a decent barrel which is plated rather than steel liner. This benefits from better heat transfer. But draws back from expensive repairs. Ultimately the DT is limited.

                              A decent spec'd Athena 170 should top out at 100mph. Plenty for a 125.

                              Always Originate, Never Pirate!

                              S 1 Reply Last reply
                              0
                              • T Offline
                                T Offline
                                theportingmaster
                                wrote on last edited by
                                #27

                                Here is my ported 170 athena when first fitted it using standard gearing and went off the clock. Fitted an Athena exhaust and a 34mm polini carb with top of air box cut out to it after this video, did 110mph with an 18t front sprocket but really scary on nobbly tyres,lol😵
                                https://www.youtube.com/watch?v=8a_sBkpuQ14

                                S 2 Replies Last reply
                                0
                                • T theportingmaster

                                  Here is my ported 170 athena when first fitted it using standard gearing and went off the clock. Fitted an Athena exhaust and a 34mm polini carb with top of air box cut out to it after this video, did 110mph with an 18t front sprocket but really scary on nobbly tyres,lol😵
                                  https://www.youtube.com/watch?v=8a_sBkpuQ14

                                  S Offline
                                  S Offline
                                  sprintall84
                                  wrote on last edited by
                                  #28

                                  @theportingmaster is that your dt in the YouTube clip ??

                                  1 Reply Last reply
                                  0
                                  • J Offline
                                    J Offline
                                    jonne123
                                    wrote on last edited by
                                    #29

                                    That 110 is really fast closer to over 30hp

                                    1 Reply Last reply
                                    0
                                    • CalumC Calum

                                      @sprintall84 It's not necessary speed you benefit from, but more torque. So gear it appropriately you should be fine.

                                      As a general whole, the Athena kit isn't brilliant. A 3MB00SP Barrel is what you want. But the price for those is astronomical.

                                      4FU is a decent barrel which is plated rather than steel liner. This benefits from better heat transfer. But draws back from expensive repairs. Ultimately the DT is limited.

                                      A decent spec'd Athena 170 should top out at 100mph. Plenty for a 125.

                                      S Offline
                                      S Offline
                                      sprintall84
                                      wrote on last edited by
                                      #30
                                      This post is deleted!
                                      1 Reply Last reply
                                      0
                                      • T theportingmaster

                                        Here is my ported 170 athena when first fitted it using standard gearing and went off the clock. Fitted an Athena exhaust and a 34mm polini carb with top of air box cut out to it after this video, did 110mph with an 18t front sprocket but really scary on nobbly tyres,lol😵
                                        https://www.youtube.com/watch?v=8a_sBkpuQ14

                                        S Offline
                                        S Offline
                                        sprintall84
                                        wrote on last edited by
                                        #31

                                        @theportingmaster you got any 170 barrel and head for sale ??

                                        1 Reply Last reply
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