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DT125R FORUM

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  4. Cutting back ?

Cutting back ?

Scheduled Pinned Locked Moved Engine
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  • DTleeD DTlee

    Is there an easy way to temporarily disable the oil pump? I just want to check if it’s not packing up? It all looks correct but my plug is still oily and the bikes still cutting back at around 6-7krpm. I’ve checked the power valve isn’t the problem by pinning it open, took it for a ride and was still having the same issue. I was thinking of trying to pre mix the fuel and disable to oil pump to work out of its this causing the problem.

    I’m running out of ideas with it. Failing this I guess it’s the ignition breaking down.

    ( I have cleaned out the carb, fuel line and the tank also and now put back on the original exhaust )

    Any ideas I’d be grateful

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

    @dtlee @dtlee

    I stuck the outlet (skinny) pipe into the inlet (fatter) pipe to cause a continuous loop. Been like that and ok for a 1000 miles, just don’t forget to block the inlet manifold oil inlet. I just cut and folded over some pipe, then zip tied it.
    It stopped messing it’s pants all over the number plate now as well since I’ve been on pre mix...

    I can’t remember what I’ve asked you before, but t did you do anything to the bike before it started happening? Even if it was a month before or seems irrelevant?...

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    • S SpookDog

      @dtlee @dtlee

      I stuck the outlet (skinny) pipe into the inlet (fatter) pipe to cause a continuous loop. Been like that and ok for a 1000 miles, just don’t forget to block the inlet manifold oil inlet. I just cut and folded over some pipe, then zip tied it.
      It stopped messing it’s pants all over the number plate now as well since I’ve been on pre mix...

      I can’t remember what I’ve asked you before, but t did you do anything to the bike before it started happening? Even if it was a month before or seems irrelevant?...

      S Offline
      S Offline
      SpookDog
      wrote on last edited by
      #32

      @spookdog

      Did you remove and clean the outside of the needle valve tube? You tap it in and up through the throttle valve body to remove it. Mine was cemented up with micro fine sand stuff...

      P.S. Did this come on all of a sudden or gradually get worse?...

      DTleeD 2 Replies Last reply
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      • S SpookDog

        @spookdog

        Did you remove and clean the outside of the needle valve tube? You tap it in and up through the throttle valve body to remove it. Mine was cemented up with micro fine sand stuff...

        P.S. Did this come on all of a sudden or gradually get worse?...

        DTleeD Offline
        DTleeD Offline
        DTlee
        wrote on last edited by
        #33

        @spookdog It’s progressively got worse I think. All I have done is moved the read switch, put a full dep on and turned the power valve so it works. It used to do it after 40mins of riding but not it seem to do it constantly. Won’t got about 6-7krpm it just cuts back. I might try what you done with the oil pump just to rule another thing out. It’s massive annoying specially as I don’t a 100 mile long distance trial today and had to put up with that all day.

        1 Reply Last reply
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        • S SpookDog

          @spookdog

          Did you remove and clean the outside of the needle valve tube? You tap it in and up through the throttle valve body to remove it. Mine was cemented up with micro fine sand stuff...

          P.S. Did this come on all of a sudden or gradually get worse?...

          DTleeD Offline
          DTleeD Offline
          DTlee
          wrote on last edited by
          #34

          @spookdog I cleaned the carb out and couldn’t see any blocked jets but I didn’t take the needle jet out. Might try this just Incase 👍🏻

          CalumC 1 Reply Last reply
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          • DTleeD DTlee

            @spookdog I cleaned the carb out and couldn’t see any blocked jets but I didn’t take the needle jet out. Might try this just Incase 👍🏻

            CalumC Offline
            CalumC Offline
            Calum
            wrote on last edited by
            #35

            @dtlee I mean, since it started doing it since you "moved the reed valve" and "rotated the powervalve", have considered that this might be the problem?

            Always Originate, Never Pirate!

            DTleeD 1 Reply Last reply
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            • CalumC Calum

              @dtlee I mean, since it started doing it since you "moved the reed valve" and "rotated the powervalve", have considered that this might be the problem?

              DTleeD Offline
              DTleeD Offline
              DTlee
              wrote on last edited by
              #36

              @calum it ran really well after I moved the Reed switch and done the power valve. Had all the power I want up to 11k rpm. Just seems to have got worse over time, just won’t rev past 6k rpm. I pinned the power open as I saw in one of your other posts but it still did the same. I’ll check the Reed is far away enough from the speedo tonight as it feels like a restriction. Other than this the bike runs perfectly.

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              • DTleeD DTlee

                @calum it ran really well after I moved the Reed switch and done the power valve. Had all the power I want up to 11k rpm. Just seems to have got worse over time, just won’t rev past 6k rpm. I pinned the power open as I saw in one of your other posts but it still did the same. I’ll check the Reed is far away enough from the speedo tonight as it feels like a restriction. Other than this the bike runs perfectly.

                S Offline
                S Offline
                SpookDog
                wrote on last edited by
                #37

                @dtlee

                Recheck the power valve isn’t 180 degrees out. Try putting the reed back in place and riding. Just to humour me 🙂...

                DTleeD 1 Reply Last reply
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                • S SpookDog

                  @dtlee

                  Recheck the power valve isn’t 180 degrees out. Try putting the reed back in place and riding. Just to humour me 🙂...

                  DTleeD Offline
                  DTleeD Offline
                  DTlee
                  wrote on last edited by
                  #38

                  @spookdog im going to put it back to standard and see how it runs and work backwards I think. Do you know if there a decent guide to doing to power valve with pictures or even a video? I just want to make sure it’s definitely right, I’m no mechanic but I like to do it myself so I can learn how it works in case of future problems

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                  • DTleeD DTlee

                    @spookdog im going to put it back to standard and see how it runs and work backwards I think. Do you know if there a decent guide to doing to power valve with pictures or even a video? I just want to make sure it’s definitely right, I’m no mechanic but I like to do it myself so I can learn how it works in case of future problems

                    S Offline
                    S Offline
                    SpookDog
                    wrote on last edited by
                    #39

                    @dtlee

                    Everything you need is out there. I can’t help you, I don’t have a computer. I found everything out by searching on my phone...

                    I would change the exhaust back to standard as well. Just to check and tick it off the list. You never know it could be blocked up with carbon oil and shit...

                    The only other thing is: does it cut back regardless of throttle position? I can achieve 10,000 rpm at 1/2 throttle. Does yours cut back at different throttle position as it reaches 6-8k? Say if you maintain 1/3 throttle in second gear?

                    DTleeD 1 Reply Last reply
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                    • S SpookDog

                      @dtlee

                      Everything you need is out there. I can’t help you, I don’t have a computer. I found everything out by searching on my phone...

                      I would change the exhaust back to standard as well. Just to check and tick it off the list. You never know it could be blocked up with carbon oil and shit...

                      The only other thing is: does it cut back regardless of throttle position? I can achieve 10,000 rpm at 1/2 throttle. Does yours cut back at different throttle position as it reaches 6-8k? Say if you maintain 1/3 throttle in second gear?

                      DTleeD Offline
                      DTleeD Offline
                      DTlee
                      wrote on last edited by
                      #40

                      @spookdog thanks for your responses. I’m going to put everything back standard and double check the carb is spotless I’ve decided before I loose my Head with it all. It won’t go past 6k in any throttle position. I feel like it’s electronic so just want to rule everything else out first

                      1 Reply Last reply
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                      • DTleeD Offline
                        DTleeD Offline
                        DTlee
                        wrote on last edited by DTlee
                        #41

                        I thought I should update this as I did fix the problem and never stated what fixed it on here. After all the messing around all it turned out to be was a split vacuum hose on the carb which I didn’t notice when I cleaned the carb originally. I had the hose off originally to check it wasn’t blocked but didn’t notice the small split in it. Thanks for all the suggestions though

                        S 1 Reply Last reply
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                        • DTleeD DTlee

                          I thought I should update this as I did fix the problem and never stated what fixed it on here. After all the messing around all it turned out to be was a split vacuum hose on the carb which I didn’t notice when I cleaned the carb originally. I had the hose off originally to check it wasn’t blocked but didn’t notice the small split in it. Thanks for all the suggestions though

                          S Offline
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                          SpookDog
                          wrote on last edited by
                          #42

                          @dtlee

                          That’s the power jet pipe, not vacuum 🤪👍

                          DTleeD 1 Reply Last reply
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                          • S SpookDog

                            @dtlee

                            That’s the power jet pipe, not vacuum 🤪👍

                            DTleeD Offline
                            DTleeD Offline
                            DTlee
                            wrote on last edited by
                            #43

                            @spookdog

                            Ah yes that’s the one ! 👌

                            1 Reply Last reply
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