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DT125R FORUM

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Cases

Scheduled Pinned Locked Moved Engine
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  • BluestoesonnoseB Offline
    BluestoesonnoseB Offline
    Bluestoesonnose
    wrote on last edited by
    #1

    If i was to keep an eye out for a set of cases to build up, what would be the best cases to go with a 2002 DT125R ported barrel and reworked head, as I'm getti g confused with everything I keep reading?

    Oh, and would they benefit from some "work"?

    Cheers

    2002 DT125R

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    0
    • CalumC Offline
      CalumC Offline
      Calum
      wrote on last edited by
      #2

      If you are putting in an R then any dtr up to 04 if an re the any cases past 04-07. Don't bother with belgarda cases as the casting is flawed. Later cases have noticeable less flaws.

      Always Originate, Never Pirate!

      BluestoesonnoseB 1 Reply Last reply
      1
      • CalumC Calum

        If you are putting in an R then any dtr up to 04 if an re the any cases past 04-07. Don't bother with belgarda cases as the casting is flawed. Later cases have noticeable less flaws.

        BluestoesonnoseB Offline
        BluestoesonnoseB Offline
        Bluestoesonnose
        wrote on last edited by
        #3

        @Calum cheers, std cases it is then, and then a call to Mick to see what can be done as he felt they could be made better.

        2002 DT125R

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

          I'm sure they can be revised. They are just made for reliability at the end of the day. No matter what you do to them, it doesn't change what they're designed for. After riding my RS, it's night and day between how both bikes react.

          Always Originate, Never Pirate!

          BluestoesonnoseB 1 Reply Last reply
          0
          • CalumC Calum

            I'm sure they can be revised. They are just made for reliability at the end of the day. No matter what you do to them, it doesn't change what they're designed for. After riding my RS, it's night and day between how both bikes react.

            BluestoesonnoseB Offline
            BluestoesonnoseB Offline
            Bluestoesonnose
            wrote on last edited by
            #5

            @Calum it's just a bit of fun for me, if I want to so faster I'll take one of the bigger bikes out, I really want to get the dt to a point it'll pull a bit harder

            2002 DT125R

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            • 2 Offline
              2 Offline
              2stroketerry
              wrote on last edited by
              #6

              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.

              BluestoesonnoseB S 2 Replies 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.

                BluestoesonnoseB Offline
                BluestoesonnoseB Offline
                Bluestoesonnose
                wrote on last edited by
                #7

                @2stroketerry thanks for this, I'm half the weight so we'll see. It's all a bit of fun and it sounds like the 170cc kit needs porting to get the best from it. If I do go for bigger ccm I'll prob go 150cc as it Seems a good half way and used the std barrel.

                2002 DT125R

                CalumC 1 Reply Last reply
                0
                • BluestoesonnoseB Bluestoesonnose

                  @2stroketerry thanks for this, I'm half the weight so we'll see. It's all a bit of fun and it sounds like the 170cc kit needs porting to get the best from it. If I do go for bigger ccm I'll prob go 150cc as it Seems a good half way and used the std barrel.

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #8

                  @Bluestoesonnose Two strokes also don't like over square engines. More power can be gained from the original 125 barrel I'm certain. I've had 170 kit in the past and it is a blast for sure. It was also a damn sight reliable, I just feel it takes a certain part of fun out of the 125, with the loss of overrev. But to be quite honest, that's not a bad thing.

                  There are many variations you can play with on these engines, I've yet to see a properly tuned up 4FU barrel on the DTR engine. I fettled with the concept on paper, but bottled it and sold my 4FU spares.

                  The stock porting on the 4FU looks better than the 3MB.

                  Also also, if you really want a decent 125 setup, then you will want the SP barrel. It will be comparable to the Rotax Gilardoni barrels, and they are superb!

                  alt text

                  alt text

                  alt text

                  Oh that makes sense, it's designed by Gilardoni. Yeah, that does make sense now.

                  alt text

                  Always Originate, Never Pirate!

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                  • CalumC Offline
                    CalumC Offline
                    Calum
                    wrote on last edited by
                    #9

                    https://www.youtube.com/watch?v=P8okvTxe-Bs&t=0s&list=PL66C1264C7D6205BB&index=11

                    Always Originate, Never Pirate!

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                    • BluestoesonnoseB Offline
                      BluestoesonnoseB Offline
                      Bluestoesonnose
                      wrote on last edited by
                      #10

                      Can't see this reply properly as it comes up blurry.

                      2002 DT125R

                      CalumC 1 Reply Last reply
                      0
                      • BluestoesonnoseB Offline
                        BluestoesonnoseB Offline
                        Bluestoesonnose
                        wrote on last edited by
                        #11

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

                        2002 DT125R

                        CalumC 1 Reply Last reply
                        0
                        • BluestoesonnoseB Bluestoesonnose

                          Can't see this reply properly as it comes up blurry.

                          CalumC Offline
                          CalumC Offline
                          Calum
                          wrote on last edited by
                          #12

                          @Bluestoesonnose The images? Yeah it's hosted through Flicker, or from Google.

                          But if you google.

                          Yamaha TZR 125 RR Belgarda SP Barrel

                          You should see exactly what I'm talking about. I've spoken to people who've ridden the SP engine and they say it's sublime.

                          Personally, it's no better than a Rotax 122 engine && Costs substantially more.

                          So just transplant a Rotax engine, or get a better bike.

                          The 4FU, again costly, is a more viable options.

                          in the end, I just spent a little money on the 3MBP barrel, but wasn't impressed with the results against a STOCK RS.

                          Always Originate, Never Pirate!

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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

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                            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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                                0
                                • 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

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                                      • 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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