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    • dtluke
      dtluke last edited by dtluke

      I'm doing a big rebuild of the bike whilst its off the road waiting for the new head gasket and tyres to arrive. It hasn't been very good low end power. Opening up to WideOpenThrottle quickly will actually make it stall. Checking the jets shows I'm on 17.5 pilot and 210 main. I've heard a lot of people going as big as 240 main with the full dep system (which I have). My spark colour is good though ( autumn brown). Now I'm planning to open the airbox up a little so will get a bigger main jet just to stop in being to lean - but has anyone ever heard of a 17.5 as the pilot jet!? The Haynes manual says it should be 22.5! Why would someone have gone smaller?

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      • Y
        yammad last edited by

        210 main? Your bike must be an early one or an early carb
        On later models the std main is 240 I think
        Also later dts have a 28mm carb early ones have 26mm
        Hope this helps

        Calum 1 Reply Last reply Reply Quote 1
        • Calum
          Calum @yammad last edited by

          @yammad said in Jets:

          210 main? Your bike must be an early one or an early carb
          On later models the std main is 240 I think
          Also later dts have a 28mm carb early ones have 26mm
          Hope this helps

          Incorrect. The later DT's ran 210 main.

          If you are going to open up the air box then low end performance will suffer. But yeah up jet to suit.

          dtluke 1 Reply Last reply Reply Quote 1
          • Y
            yammad last edited by

            Sorry I stand corrected
            Wouldn't want to mislead anyone
            There was a difference in carb size over the years wasn't there ? Or have I got my wires crossed ?
            I've worked on so many bikes over the years I get em muddled up

            dtluke 1 Reply Last reply Reply Quote 1
            • dtluke
              dtluke @Calum last edited by

              @Calum ah, OK. Thanks. So low end suffers if letting more air in?..... Why is that? My low end is already pretty bad but the last owner(s) has mullered the mixture screw... I've just spent 3 hours carefully drilling it out and ordered a new one for £10 so should be able to get that sorted a bit better. So my 2005 model should be on a 210... Maybe it should be on a 17.5 too. Not impressed with the Haynes manual - it claims to cover my later model but misses out loads of needed info and specs on it.

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              • dtluke
                dtluke @yammad last edited by

                @yammad cheers mate. Easy mistake as there are so many models of this bike and they switched just about everything over the years!!!! No idea what carb I have - I know its a flat sided mikuni but isn't the one used on most of the dts

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                • Y
                  yammad last edited by

                  I think u were right to question a 17.5 I only have the manual that goes to 1991 and in there it's a 22.5
                  Maybe somebody tried to correct a jetting issue and got it wrong 😉

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                  • Darty
                    Darty last edited by

                    94-1999' models run 210 Main Jets with the TM28ss

                    Later Models 99'-05' onwards - Main Jet 240. TM28ss

                    Pilot should be a 25. for 99' onward models, but I think perfect for the earlier Pre 94-99'

                    dtluke 1 Reply Last reply Reply Quote 2
                    • dtluke
                      dtluke @Darty last edited by

                      @Darty thanks again guys. Ordered the right jets. Should run like a dream when I get it set up properly

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                      • dtluke
                        dtluke last edited by

                        DOH! didn't look at the back of the haynes manual (pg140) where they added later bike models. From 2004 onwards the main jet was 210 and pilot was 17.5 - so my bike was set up correctly! Problem now is my jet needle is a little bent and shows excessive wear on the bent side which means I need to replace my needle and needle jet ( 5j40 and q2m(939) ) but I can't find those anywhere on the web.

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