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  • Power loss.....

    Just had a major service on my 7000 mile ZZR1100D1. Plus a Dynojet kit, 520 chain & sprocket conversion. Around 9 years ago I had the bike Dynoed at H&M Racing in Edenbridge, on that day it read 154rwhp. The bike has had work done to it over the years. Then about 4 years ago I had it done again at P&H in Crawley and on that day on that dyno it read 147rwhp. Just had the service done as mentioned above and had it dynoed at Vanguard in Uckfield and it read 116rwhp. They did a compression test, leak down test and everything is working as it should, they told me the bike is running fine. However, they can't explain the differences in the previous numbers. They agree a standard restricted D1 would be making 116-119rwhp. My bike is far from standard.

    Does anyone have any ideas where 35+ bhp could have gone? In between the last dyno run and the previous run the bike covered less than 1000 miles.....

    Thanks

  • #2
    Changed jets... Air/Fuel mix? Carbs re-balanced? Running rich?

    Converted sprocket from what to what? Changed tooth count or is the stock bike not 520? I'm not familiar with the 1100.

    Seems if those were the only changes, one of them is the likely HP thief.
    “Live a good life. If there are gods and they are just, then they will not care how devout you have been, but will welcome you based on the virtues you have lived by. If there are gods, but unjust, then you should not want to worship them. If there are no gods, then you will be gone, but will have lived a noble life that will live on in the memories of your loved ones.”...Marcus Aurelius, Meditations

    Comment


    • #3
      Comparing dyno numbers in general and from different dyno machines is meaningless.

      The only thing a dyno number/machine is good for is when you are making mods and doing before and after numbers
      on the same machine at the same time to see how your mods performed.

      How does your butt dyno measure it? Hows your times in the 1/4 mile changed?

      I wish changing sprockets could increase horsepower.






      Last edited by piken; 11-10-2021, 03:30 PM.
      Our ability to distribute interesting information is out pacing our ability to create it.

      Comment


      • #4
        It is possible the other dyno runs were high and this one is closer to the actual HP. Ask what they get for stock bikes; that should indicate whether their dyno is reading low

        What has been done to the engine? 150 is pretty good for a ZX11.

        Sent from my SM-G980F using Tapatalk

        "You don't get slower with age, you just get more cautious." Michael Rutter

        06 Ocean Blue ZZR1200, the coolest colour.
        99 Yamaha R1

        Comment


        • #5
          Originally posted by ramblin66 View Post
          Changed jets... Air/Fuel mix? Carbs re-balanced? Running rich?

          Converted sprocket from what to what? Changed tooth count or is the stock bike not 520? I'm not familiar with the 1100.

          Seems if those were the only changes, one of them is the likely HP thief.
          Hi

          Thanks for responding. The Dynojet kit was installed and set up by Vanguard and they're a Dynojet approved outlet and the owner is pretty knowledgeable about setting up carbs and the A/F was approx 13 when measured. The kit itself gives a smoother throttle response and may add a couple of bhp. The carbs were sonically cleaned and new gaskets etc.

          The chain/sprocket conversion was from the standard pitch 530 to a 520 pitch with -1 tooth at the front. The benefits are less weight and reduced rotating mass resulting in a small bhp increase of between 1-2bhp.

          I don't think those changes resulted in more than a 30% reduction in power. They were intended to give it a little more pep.....


          Thanks

          Dave

          Comment


          • #6
            Originally posted by Moise View Post
            It is possible the other dyno runs were high and this one is closer to the actual HP. Ask what they get for stock bikes; that should indicate whether their dyno is reading low

            What has been done to the engine? 150 is pretty good for a ZX11.

            Sent from my SM-G980F using Tapatalk
            Hi

            Thanks for responding. As I mentioned in my post, the standard restricted D1 produces approx 147bhp at the crank. Which equates to approx 125rwhp claimed. When actually measured by multiple bike magazines at the time it was closer to 116-119rwhp. The later bikes were de-restricted to compete with the Blackbird by removing the restriction in the carb tops.

            They agreed that the bike was low compared to other ZZr11's they'd measured and also based on the info available online.

            The bike has had the following work:

            De-restricted carb tops
            Wiseco 1109cc Big Bore kit.
            Hi-lift cams
            4-1 Remus full system
            4 Degree ignition advancer
            Dynojet stage 1 kit
            520 chain/sprocket conversion
            Iridium plugs
            K&N filter
            Mileage 7800

            The bike has had several dyno runs on two different dyno's several years apart and measured between 147 to 154rwhp. This inline with my expectations for the work done.

            Thanks

            Dave

            Comment


            • #7
              Originally posted by piken View Post
              Comparing dyno numbers in general and from different dyno machines is meaningless.

              The only thing a dyno number/machine is good for is when you are making mods and doing before and after numbers
              on the same machine at the same time to see how your mods performed.

              How does your butt dyno measure it? Hows your times in the 1/4 mile changed?

              I wish changing sprockets could increase horsepower.





              Hi

              I agree. That's why it was dyno'd. I wanted the before and after evidence, if my changes made a positive difference. But a 30% loss against previous runs can't be blamed on different dyno's years apart or a properly set up dynojet kit

              Bike isn't back yet and I've not ever run a 1/4......

              Changing the sprockets will reduce rotational mass and very slightly increase bhp if everything else remains the same. Google it, there's plenty of evidence to support it.

              Thanks

              Dave

              Comment


              • #8
                I think the first two readings were high. A jetted ZZR1200 with aftermarket exhaust put out about 144 rwhp.
                Last edited by spedxprt; 11-11-2021, 05:51 PM.
                My ol' ZZR1200 pics:
                http://zzrbikes.com/gallery2/main.php?g2_itemId=156883

                Comment


                • #9
                  Originally posted by spedxprt View Post
                  I think the first two readings were high. A jetted ZZR1200 with aftermarket exhaust put out about 144 rwhp.
                  Thanks for responding. That sounds about right for a pretty standard 12. Mine isn't standard and even if the readings are high on both of the other Dyno's (unlikely) it doesn't explain the huge discrepancy encountered on the latest run. A bog standard de-resytricted 11 is 125RWHP. The restricted D1-D5 (carb top restriction) is 116-119RWHP.

                  Thanks

                  Dave

                  Comment


                  • #10
                    It is a bit of a mystery as it is difficult to understand how 40 HP could disappear like that. Had you noticed any difference riding it?

                    Can you post some of the dyno charts?

                    Sent from my SM-G980F using Tapatalk

                    "You don't get slower with age, you just get more cautious." Michael Rutter

                    06 Ocean Blue ZZR1200, the coolest colour.
                    99 Yamaha R1

                    Comment


                    • #11
                      What if you get it dynoed at one of your earlier dyno centres?
                      I had my patience tested. I'm negative.

                      Comment


                      • #12
                        If you can't notice a 40+ plus horsepower loss in your ass, you either need to check the bike
                        or get a new ass. That's around a 30% power loss, that's very noticeable in the "ass-test"
                        on the road. Something is wrong somewhere. That's like going from a 1200 to 600 displacement
                        in power difference.
                        "If it ain't broke, don't fix it...
                        but sometimes it just needs a mod"

                        Comment


                        • #13
                          Originally posted by Moise View Post
                          It is a bit of a mystery as it is difficult to understand how 40 HP could disappear like that. Had you noticed any difference riding it?

                          Can you post some of the dyno charts?

                          Sent from my SM-G980F using Tapatalk
                          Hi
                          I will add the charts from all the runs.

                          I have contacted Dynojet UK. They're looking into it.

                          Dave

                          Comment


                          • #14
                            Originally posted by CHARLIE View Post
                            If you can't notice a 40+ plus horsepower loss in your ass, you either need to check the bike
                            or get a new ass. That's around a 30% power loss, that's very noticeable in the "ass-test"
                            on the road. Something is wrong somewhere. That's like going from a 1200 to 600 displacement
                            in power difference.
                            I completely agree. I have contacted Dynojey UK. They're in touch with the authorised dealer to get more info.

                            Dave

                            Comment


                            • #15
                              Originally posted by BillDownUnder View Post
                              What if you get it dynoed at one of your earlier dyno centres?
                              That's on the cards for Spring.

                              Dave

                              Comment

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