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    TDR125 4GW

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    • tdr125greg
      tdr125greg last edited by tdr125greg

      Evening all,

      upon removing the end can I realised all the packing was gone,so decided to go ahead and order some dep exhaust wadding (not the loose kind) whilst I wait for it to be delivered I thought I'd give the can a wee clean up

      Check out the results

      0_1485170210824_DSC_0041.JPG

      0_1485170247637_DSC_0045.JPG

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      0_1485170291997_DSC_0014.JPG

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      0_1488295068940_IMG_20170228_151447.JPG

      NINJA 1 Reply Last reply Reply Quote 0
      • NINJA
        NINJA @tdr125greg last edited by

        @tdr125greg Very shiney!!! 👍

        1 Reply Last reply Reply Quote 0
        • Calum
          Calum last edited by

          Looks good Bud 😄

          1 Reply Last reply Reply Quote 0
          • Mightyman
            Mightyman Global Moderator last edited by

            Not sure if your bothered about losing the sticker, but you can get a new one from DEP if you contact them directly.

            tdr125greg 1 Reply Last reply Reply Quote 1
            • tdr125greg
              tdr125greg @Mightyman last edited by

              @Mightyman. I did manage to find heatproof Dep pipes decal to go back on
              Cheers for the knowledge man!!!.

              1 Reply Last reply Reply Quote 0
              • tdr125greg
                tdr125greg last edited by tdr125greg

                Hello forum,

                I have had a very productive day today.
                I've stripped the powervalve down seeing as the seal and o-ring were shot to bits and the valve itself,caked in carbon.

                I have now received all the correct O-ring and seals needed to complete the refurbishment courtesy of PJME

                Here are some pictures

                0_1485169884723_DSC_0004_8.JPG

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                0_1485170071342_tmp_25866-DSC_0033-1288080901.JPG

                0_1485170043130_tmp_25866-DSC_0030-1700659582.JPG

                Calum 1 Reply Last reply Reply Quote 0
                • Calum
                  Calum @tdr125greg last edited by

                  @tdr125greg If you get some wet and dry paper, you can smooth off the valve and grind out the lettering.

                  This will allow the exhaust gases to flow better into the expansion chamber, AND GAIN YOU LIKE 0.000001 BHP.

                  But it's free power so...

                  tdr125greg 1 Reply Last reply Reply Quote 0
                  • tdr125greg
                    tdr125greg @Calum last edited by

                    @Calum said in TDR125 4GW:

                    @tdr125greg If you get some wet and dry paper, you can smooth off the valve and grind out the lettering.

                    This will allow the exhaust gases to flow better into the expansion chamber, AND GAIN YOU LIKE 0.000001 BHP.

                    But it's free power so...

                    Free power is free power my friend

                    I will get right on that.

                    What's your thoughts on getting my 4FU ported??
                    I mean in terms of gains
                    I've read up that the guy for that is stan Stephens but I'm new to this so fishing for knowledge.

                    Cheers.

                    Calum 1 Reply Last reply Reply Quote 0
                    • Calum
                      Calum @tdr125greg last edited by

                      @tdr125greg I doubt Stan will do that barrel for you.

                      From when I looked many moons ago, he only works on classics, and he is probably getting on a bit.

                      I had porting work carried out by Mick Abbey.

                      But porting work alone won't do very much. And it's all about the bigger picture.

                      The 4FU heads are restrictive. Getting a 3MB, with a domed piston, increased jetting, Ignition system, Pipe and induction shall see you great cans.

                      But doing one without the other will bring more drawbacks than good.

                      If you want to start on one thing, I would do the ignition system.

                      Then I'd build a separate engine from the ground up, and transplant it when it was finished with the supporting mods.

                      But that's expensive and takes time.

                      Best way though

                      1 Reply Last reply Reply Quote 0
                      • tdr125greg
                        tdr125greg last edited by tdr125greg

                        You speak of ignition upgrades as a first port of call, are you talking about changing the cdi? If so what are my options.? Aftermarket or OEM.

                        With regards to the engine your absolutely bang on about building a separate one from the ground up, like you say it will take a lot of money and time, but the theory behind it makes more sense. Especially now I have a spanking new flat top mitaka piston for the 4FU barrel I mas aswell run it as is for now.

                        Calum 1 Reply Last reply Reply Quote 0
                        • Calum
                          Calum @tdr125greg last edited by

                          @tdr125greg Yeah, I don't know what your options are. But I used Zeeltronic Ignition System. I will be using them again for my new build.

                          By far the single one component that I noticed.

                          Yeah, I personally, would have ran a domed piston, higher compression. Usually, Higher Compression = Higher Peak Power.

                          Usually.

                          It's not a strict rule, and it does add wear, but if you tune it right, you can generally make bigger gains upping the C/R

                          1 Reply Last reply Reply Quote 0
                          • tdr125greg
                            tdr125greg last edited by

                            So you are telling me I could have ran a dome top piston in my 4FU nikasil plated barrel.

                            The only reason I ask is because I was told I could only run a 56mm flat top in my cylinder by pjme?.

                            Calum 1 Reply Last reply Reply Quote 0
                            • Calum
                              Calum @tdr125greg last edited by

                              @tdr125greg PJME know what they are doing.

                              You can run whatever you want.

                              But you would want to have the combustion chamber reworked.

                              If you have a 4FU head then you should notice a restrictive combustion ring around the chamber.

                              For £30 odd quid Mick Abbey will grind that out and put a nice squish band there. 80% of the power of a two stroke comes from the head. So getting this part right is crucial.

                              Telling your tuner that you are going to run a domed piston, will allow them to correct the squish band.

                              My advice would again be do this with another, specifically designed, engine.

                              The Rotax 122 engine that I am building comes stock with a flat top piston. But I intead to rework the head and run a domed.

                              Running at higher compression puts you at risk from detonation. This is an engine killer. To avoid this you need to retard the ignition, or up the fueling.

                              So it's not always clear what the best path is.

                              I have had a few 4FU's but never saw a build through to the finish.

                              1 Reply Last reply Reply Quote 0
                              • tdr125greg
                                tdr125greg last edited by

                                Thankyou calum I will take everything into consideration and make a path for myself. I solidly agree on a second engine but for now I'd rather get the current engine running smoothly and swap the front end.

                                When I have a nice set up I will give it the beating heart it deserves.

                                1 Reply Last reply Reply Quote 0
                                • Darty
                                  Darty last edited by Darty

                                  You cant run a Domed piston in a 4FU? Wouldn't it hit the head? I've got a 4FU head, and they never came with combustion rings, only 2RK/3BN's?

                                  A Flat top piston doesn't interfere with your transfer ports as much as a Domed piston, so you can take advantage of scavenging with correct porting and a proper exhaust,

                                  The 4FU seems to have larger volume crankcase transfers than a 3MB?

                                  I'm running .6mm squish and a 134cc heavy Top end porting on a 3MB barrel. Looking at 25bhp maximum on 97octane. Most power will be made by the cylinder head itself, the barrel is aiding it along.

                                  No doubt moving torque, and not that much more of it to very high RPM, will only make you come to be very efficient at going up and down the gearbox quicker to keep the thing in the right rev range.

                                  Depends what you want from it, i'd say get the ports cleaned up, but don't change the Port timings at all, and just run her standard. These engines don't make power at all like a Rotax!

                                  I've been bulding a race setup for mine for a while now, yet to know proper results tho

                                  Calum 1 Reply Last reply Reply Quote 0
                                  • Calum
                                    Calum @Darty last edited by

                                    @Darty Here was my 4FU

                                    alt text

                                    alt text

                                    As said I don't know natively if it supports domed, but certainly if you removed that ring and reworked the head

                                    Darty 1 Reply Last reply Reply Quote 0
                                    • tdr125greg
                                      tdr125greg last edited by tdr125greg

                                      This post is deleted!
                                      1 Reply Last reply Reply Quote 0
                                      • Darty
                                        Darty @Calum last edited by Darty

                                        https://c1.staticflickr.com/1/440/30800032804_7635f2db5c_c.jpg

                                        https://c1.staticflickr.com/1/431/31525983671_ea3ee375cf_c.jpg

                                        Mine might have been modified, the crown seems very different. No signs of a heavy skim. it's a closer match to a P' stamped head but with a squish height less than .5, A domed piston would crash into it at that point.

                                        A base gasket would help, but then you begin to change port timings, not good. I gave up on a 4FU, Nicasil is expensive if you lunch the bore up.

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                                        • Calum
                                          Calum last edited by

                                          Sorry my bad.

                                          I have had a few 4FU's and they have all been this way.

                                          Which is why I said it...

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                                          • tdr125greg
                                            tdr125greg last edited by tdr125greg

                                            Another purchase sees the trail tech vapor and indicator dash added to PROJECT TDR.
                                            I purchased the kit on eBay from Moore speed racing for £150 all in which I thought was a good deal. 🔥🔥

                                            Any of you guys run the vapor on a tdr/Dt before?

                                            0_1488293323206_DSC_0017_1.JPG 😀

                                            Calum 1 Reply Last reply Reply Quote 1
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