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Thread: ESE's works engine tuner

  1. #35851
    Join Date
    25th March 2004 - 17:22
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    RZ496/Street 765RS/GasGas/ etc etc
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    Wellington. . ok the hutt
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    That's a lot of revs for not very much power. Geez I wish I'd chanced over 13500 over rev. Just my old engine would destroy much after 12000, so I was conservative
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  2. #35852
    Join Date
    13th August 2020 - 20:54
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    Derbi DRD pro
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    Finland
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    15
    Dave, you are right. I’m not happy with power level and it seem that max power is not going higher with current transfer and exhaust port design.
    Our dyno hasn’t been calibrated against any other dyno, just with with weight dropping 5 meters and pulling roller to acceleration with rope wrapped around circumference.
    It seems to be pessimistic against competitor bikes that have been measured in commercial dynos.
    It leaves 14rwhp bikes behind on track.
    This is only speculation of course, bike needs to be measured in commercial dyno to really know the power level.

    There is also some effect from fact that EGT doesn’t go high enough in dyno. One plan is to use disc brake from car and run bike shortly against it to rise EGT. Then release brake and do the run.?

    I think that tuning issues with current cylinder are:

    -Auxiliary exhaust ports have timing (191) too close to main (192).
    -Too big exhaust passage, passage to window ratio 96%
    Too long transfer duration, 131.
    Tranfers doesn’t have enough axial angle (8, 6, 59).
    B-transfers not wide enough, there is big space between B and C.

    I need to redesign these now as my EngMod model starts to be ok

  3. #35853
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    6th February 2012 - 08:54
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    1988 cagiva freccia
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    france
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    106
    which cylinder do you use ?

  4. #35854
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    13th August 2020 - 20:54
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    Derbi DRD pro
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    Finland
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    It is modified Athena power valve 50cc. I also have one untouched new one in the box waiting.

  5. #35855
    Join Date
    25th March 2004 - 17:22
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    RZ496/Street 765RS/GasGas/ etc etc
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    Wellington. . ok the hutt
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    18,711
    And as I awake a little more sober, I have to apologise for my post, that was out of line to criticise so I am sorry.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  6. #35856
    Join Date
    8th February 2007 - 20:42
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    TZ400
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    tAURANGA
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    Dave , you may have been pissed but you were right - never happens with me sadly.
    Snie , the inertia measurement system with wound string and drropping weight is a good one , but the slow drum speed makes friction a bigger component.
    You need to do a run down test to fix this.

    14,500 is not alot of revs though , with good components its not stressing anything at all.
    But yes , most of the specs you have revealed so far tell straight away what is wrong, as does the steep drop off after peak power.
    The Ex/Aux split is way too small and the timings way , way low. Especially with not very wide transfers up at 131 , the Blowdown must be badly compromised.

    As its a power valve cylinder you should be running reverse stagger as well like the Aprilia - as this scavenging system dramatically helps peak and overev power ,and the PV gives back more in the mid than the transfers loose.
    My guess would be to fix the wierd axials ( why 59* - use Frits bore/stroke formula to get all the angles correct ) widen the B and then probably lift just the main Ex to get more split and correct the blowdown.
    This also would go some way toward correcting the miles to big duct exit % as well .

    The big stinger will be naturally helping mid power and will allow leaner jets to get the egt up , but I would go bigger and use a slip in tophat nozzle like I introduced in the TM R1 as this always makes better power.

    Probably a bunch of other details way off the mark , but revealing the sim file is the only way to fix that.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  7. #35857
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    13th December 2018 - 18:06
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    1983 yamaha rd 250
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    sweden
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    I was assigned to care for a fleet of Suzuki rm 85's, and possibly tune a few of them; Anyone that has done any tuning on these? 04-19.

    Also, I need better top end performance out of my yzf 1000r. I've read the yzf 750 cams are higher/longer and is a direct swap, but I'm poorly oriented with these engines. Same question: Anyone knows how to tune them, or where to look for information?

  8. #35858
    Join Date
    20th April 2011 - 08:45
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    none
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    Raalte, Netherlands
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    Quote Originally Posted by wobbly View Post
    the inertia measurement system with wound string and dropping weight is a good one , but the slow drum speed makes friction a bigger component. You need to do a run down test to fix this.
    I don't think a coast-down run will be the solution just yet, Wob.
    My dyno software has a calibration option that uses the dropping weight-system. The drum has to start rotating before the Hall-sensor receives its first pulse, so the stationary stick-friction is eliminated before the measurement starts. Then the drum has to perform two complete revolutions, wherein the time for each revolution is measured in microseconds, just like during a normal power run.
    Then the weight is substituted with a different weight and the two-revolutions measurement is repeated, after which the software has sufficient information to calculate the inertia and the friction, assuming the friction is constant during these ultralow drum rpm values.

    Once these values are known, we can perform a coast-down run. This is especially important if the dyno is equipped with an eddy current retarder. These retarders usually have cast-in cooling fins and their centrifugal ventilation function can absorb a consideral amount of power at high revs. The sum of friction and centrifugal pumping losses can be as high as 6 hp,
    as I once measured by putting a turbo-bike on the dyno, accelerating it to 300 km/h and then lifting the rear wheel one centimeter off the drum. The coast-down time allowed us to put the kettle on and have several cuppas.
    Click image for larger version. 

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  9. #35859
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    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Auckland
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    10,139
    Quote Originally Posted by sniemisto View Post
    Our dyno hasn’t been calibrated against any other dyno, just with with weight dropping 5 meters and pulling roller to acceleration with rope wrapped around circumference. It seems to be pessimistic against competitor bikes that have been measured in commercial dynos. It leaves 14rwhp bikes behind on track.
    This is only speculation of course, bike needs to be measured in commercial dyno to really know the power level.
    I have seen two well constructed home made dynos here. Both read lower than the Dynojet we use. We even did back to back tests between the home brew dyno's and the Dynojet.

    The home brew dyno's calibration was checked in various ways. Calculation, Rope pull and run down. I cant remember the difference but it was significant, maybe 10-12% lower than the DynoJet. The conclusion from these results and after a bit of reading about other commercial dynos. Was that commercial dynos deliberately over read to flatter the customers ego. But it seems results between different DynoJets are consistent. And anyway, if you have a reliable dyno you can develop your bike whatever the real hp result may be. I suspect your dyno may be more "accurate" in real terms than our DynoJet.

  10. #35860
    Join Date
    8th February 2007 - 20:42
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    TZ400
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    tAURANGA
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    Right on TeeZee . When the DynoJet was being developed they were of course using a Harley and of course it made fuck all power.
    Thus a fudge factor of 12% I believe was added right at the start so as not to piss off their largest customer base.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

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  1. F5 Dave

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