690R carburetor conversion mod.

Discussion in 'Thumpers' started by Visigothic, Feb 27, 2011.

  1. Seth S

    Seth S Will _____ for _____

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    The weight difference should not be a deciding factor in whether you will run a carb or fuel injection. Its not as if the FI systems are 50 lbs heavier on a bike....maybe 5 lbs for the harness, computer, switches, pumps etc. Most of the riders I know could shed 20 lbs from their bike by going to the gym.
    #21
  2. Navin

    Navin Long timer

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    (as yet, no-one has made a kickstart FI bike with no battery that I know of!).

    Kawi, Suzuki and Honda MX 450s!
    #22
  3. Dazed Productions

    Dazed Productions Been here awhile

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    Totally agree and I never said otherwise. Of all the places to make savings this is probably not the place to look. I was just saying I was surprised no one had considered it as a factor, even if its a relatively insignificant one in the decision process.
    #23
  4. Dazed Productions

    Dazed Productions Been here awhile

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    If they do it with not even a small battery, consider me impressed! Would be interested to know how they do it out of pure curiosity.
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  5. Navin

    Navin Long timer

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    Kawi KX450, "Strong output from the large ACG rotor provides enough electrical power for the battery-less FI system to enable true one-kick starting without using a battery" quote lifted from their site.
    #25
  6. The Letter J

    The Letter J Long timer

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    they just use a capacitor, thats why they usually take 2-3 kicks to start for the first ride of the day. After that, I can usually kick the crf450 over in 1 kick.
    #26
  7. Dazed Productions

    Dazed Productions Been here awhile

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    Cool, I am impressed!
    #27
  8. Seth S

    Seth S Will _____ for _____

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    I thought the gas gas rally bike was a kick start efi bike.
    #28
  9. LukasM

    LukasM Long timer

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    OK, here are the pics of a gen 3 41mm FCR next to the 690 throttle body (gen 2 is with a buddy). Good news is that it's quite a bit shorter, 82mm vs. 93mm and the inlet and outlet are smaller. This means that you should be able to put some adapter rings on both ends of the carb to make up for the difference in diameter and length.

    [​IMG]

    Now somebody who actually owns a 690 should check how tight the fit is around the TB as the carb is slightly higher (but not wider).
    #29
  10. Visigothic

    Visigothic Been here awhile

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    Looks promising and possible!:clap Good work.
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  11. Seth S

    Seth S Will _____ for _____

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    so...if you have the 690 throttle body off can you look inside and tell us if there are 2 seperate throttle plates?
    #31
  12. LukasM

    LukasM Long timer

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    There is only one plate, but it gets controlled from two sides. The cable actuated cam on one side, and the servo that can override it on the other.
    #32
  13. Visigothic

    Visigothic Been here awhile

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    The servo side is the one that gives most of the issues through the stock CDI. on power control and top speed. The Vertex is supposed to fix that issue. Not sure if it removes the servo control aspect altogether or not.

    On the same note a non EFI Vertex CDI with its programability could possibly be used on the "carb. mod" through trial and error on a dyno. It might be that one would have to use a larger carb due to airflow and volume restriction of the smaller dia. of the FCR 98mm vs.92mm and run it leaner. Fuel flow we can adjust, air volume we are stuck with due to the internals of the intake, unless we buy the RR head. I say this because we don't know what the intieror manifold of the 690RR's flow rates are. This also assumes the throttle body of the EFI isnt air restricted also. Errrr You know what I mean. Its all about air flow rates. I'm, probably wrong on this assumption but hey just throwing it out there. Then again a narrower circumference would mean higher velocity air flow and better atomization of fuel to fill the same displacement so may be its ok.........now where was I. :hmmmmm
    #33
    LAndreas likes this.
  14. Dazed Productions

    Dazed Productions Been here awhile

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    The vertex unit might be a good call. As they already make a EFI unit for the 690 they will have the ignition curves already. They can also give a few maps to choose from. Not sure if there are any cam differences in the RR that would call for a different map to the 690. Probably worth speaking to vortex if anyone gets to the point of taking this further. If I get a 690 next year I will be tempted to give it a go.
    #34
  15. Dazed Productions

    Dazed Productions Been here awhile

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    This thread seems to have gone quiet but a few other observations I have made.
    ECUs are also available here for considerably less money. The ECU is tunable and can work with TPS. The tuning software is free with the unit.
    http://www.ignitech.cz/english/aindex.htm

    www.tuneecu.com
    Software for programming the original KTM fuel injection system, but also gives you access to the ignition map. It is therefore possible to take the stock map and programme it into the ignitech system.
    #35
  16. crankshaft

    crankshaft Guns are for pussies

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    With the Tuneecu, I locked out the stepper control, so now I have 100% throttle at my wrist. What year 690 do you have?
    #36
  17. Dazed Productions

    Dazed Productions Been here awhile

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    A bit of progress. I can confirm that with the Rally inlet manifold that a 41mm FCR goes in. There is also a airbox rubber on the 2010 RR that looks like it will replace the FI boot. I ran out of time to actually fit the airbox. I worked out you can't use an EXC ECU as this relies on a stator high voltage coil (that the Rally does not have). Possibly an old LC4 one would work but the rally one is no more expensive really. I got some photos of the Rally connector in the Rally thread.
    I have worked out that the 450rr tank plate appears to be designed to be forward compatible with the fuel pumps. It has a plate on the bottom with a banjo connector (and this plate uses the same gasket as the FI bikes!).

    My next steps:
    Source ECU connector
    Source ECU
    Conduct test firing with external fuel tank
    Convert tank and test ride
    Fit fuel pump (to begin with I will probably just use it on a gravity feed, so its going to stop when the fuel level gets too low)

    I am currently working on just adding the ECU to the current wiring loom rather than ripping the old one out and fitting the rally loom. I am in two minds on whether I will end up changing over to the rally loom at the end of the day to get rid of excess crap.

    Attached Files:

    #37
  18. bigborefan

    bigborefan Making new friends

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    Didn't you Luddites get the memo? Carbs are dead.:D
    #38
  19. Deadmanonduty

    Deadmanonduty n00b

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    I am trying to install a LC4 690 engine in a bike that had a 525 RFS in it previously (custom install of course).
    Any ideas on what I will all need to convert the Fuel Injected 690 I have to run on the Khein Carb?

    I currently have a 2008 LC4 with the throttle body, wiring harness, and the 2 small computer boxes plugged into the wiring harness.

    How much of my RFS ignition will work on this LC4?

    Thanks in advance for any help you guys can offer! This 690 is going to be sooooo much fun compared to the 525! :D
    #39
  20. Seth S

    Seth S Will _____ for _____

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    you might need a stiffer frame.
    #40