Home Forums Shifter Karts DIY CR125 EFI ?

This topic contains 2 replies, has 3 voices, and was last updated by  Chris Reinhardt 4 years, 8 months ago.

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  • #20667


    Has anyone fooled around with piecing an EFI system together for a cr125 ? I have been looking at doing this for a while now and I cant seem to find anyone who has . My plan was to use a throttle body off of a 2012 CBR250 (38mm bore ) ( see photos ) A Megasquirt II DIY ECU and various GM sensors like MAP Fuel Press.  , Intake Temp. ,  and Coolant Temp. And use a thermocouple that I have left over from a previous project for EGT ( Instead of a wide band A/F Ratio sensor because the oil will ruin the sensor. ) I also plan on installing a small motorcycle battery and a alternator off of the axle. I know weight is going to be added. I don’t plan on racing. I have as much fun working and tinkering as I do driving it. My main problem that I foresee is giving the ECU an rpm signal. Id like to have the ECU be able to control ignition timing as well as fuel but i’m not sure how the system works on the motor as it sits. The next problem would be finding a small fuel pump capable of supplying the injector but isn’t too big that it draws too much current. Also a fuel pressure regulator.


    Here is the link to Information about the Megasquirt II ECU

    (   http://www.msextra.com/doc/index.html    )

    Pictures of the 2012 CBR250R throttle body

    <address>(      http://www.ebay.com/itm/2012-CBR250R-CBR-250-R-CBR250-THROTTLE-BODY-BODIES-/380724717842  ) </address> 

  • #20673

    James McMahon

    I think I’d go this route over megasquirt on a two stroke…

  • #20710

    Chris Reinhardt

    Been covered several times already….


    Not an easy task, but doable….

    Let me re-phrase that….  The actual bolting on and adapting the parts so the injector squirts, is pretty easy.  Making the injector squirt the right amount at any given load, throttle position, baro pressure, water temp and air temp, that’s the hard part….


    Chris Reinhardt

    CR2 Motorsports


    XV Racing Products



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