2007 Suzuki DR-650 stalling under particular throttle position

Discussion in 'Thumpers' started by thetubespoke, Jul 25, 2018.

  1. thetubespoke

    thetubespoke Long timer

    Dec 28, 2014
    Hi everyone,

    This has been bugging me for a while. If I open the throttle just right, fairly quickly to say 1/4 or 1/5, the bike will stall more often than not (with the clutch in or neutral, etc). Bike has 3,333~ miles, cam chain is good, air filter should be good, carburetor has the Factory Pro jet kit (45 pilot?, 140 mains, the titanium needle at I forget the position), and generally the whole bike runs great overall. It did have the factory plug spec in them and they were awfully black, went one heat range hotter. Haven't checked since. It runs great from idle, good low end torque, 33 MPG (I do twist the throttle more often than not, doesn't seem unreasonable to me), and seems to behave fine except for this one quirk. Valves are also set fine. So fully stock intake and exhaust, only thing different in the carburetor is the Factory Pro jet kit which did seem to improve low end torque slightly.

    Not sure if this should be under the bike specific thread or not, but I'm sure people from all walks of life can chime in with this. I do have a bung for a wideband oxygen sensor (and no, the bung doesn't cause this), which I'm not sure if it will respond fast enough to catch if this is a rich or lean condition.

    Other considerations, not overfilled with oil, if I quickly open the throttle with slightly less twist or further than 1/4, it revs up fine. It's just a fast throttle open of about 1/4 or 1/5 throttle, no more and no less. And slowly opening it doesn't cause the stall. We've also adjusted the idle mixture screw out of ideal in both directions to see if it would make an improvement, and it did not.

    Thank you for your time,

  2. William Wolfen

    William Wolfen Long timer

    Dec 5, 2015
    Cypress, TX
    Definitely come to the big DR thread. Lots of help there.

    As for your setup, is stinking rich. The factory pro kit is mean for a snorkel removal. The original pilot jet from Suzuki is all you'll ever need. The original main jet will be fine too. Needle on the middle clip should work good.

    I ran a 6G5 before that's a near match in profile to the factory pro needle. It was a little rich but ran good with the original jets and the needle on the middle clip.

    That should be enough to get you running and not stalling. Won't be perfect, but it should run good and should improve your mileage too. Even when I was getting after the throttle I was still getting 43 mpg. Anything under 40 and you're way too rich.