too jumpy in first ~3% of throttle openi

Discussion in '2-Stroke Machines' started by mattology, Mar 4, 2018.

  1. mattology

    mattology Well-Known Member

    yeah, i dont plan on giving up on this carburetor just yet. depending on the tolerances and what not i may try and 3d print a new slide, and then have nickel metal vapor deposition on top of the print to make the part metallic. why throw money at a problem when you can throw time, money, and complication at it?
  2. Algonquin

    Algonquin VRRA and DOCC no.92

    Well said, awards should be presented for such category-leading examples...

    Impressive, just wait until you do the part surface-grinding or other fettling. Minor issues, good stuff.
  3. mattology

    mattology Well-Known Member

    I went with a factory TPS equipped TMX38 from a 2007 Honda CR250R to replace my non-tps TMX38. Also I went to a solenoid powerjet instead of my thunder powerjet, which kept vibrating itself out of adjustment on me.

    The tps will allow me to retard the timing in the lower throttle percentages to make the bike less jumpy not just as a result of extra fuel, but also less ignition timing.

    I also added a wideband o2 sensor so i can see what kind of air fuel ratios i am actually running on the dang thing while on the pipe, and not just reading my egt and cylinder head temp.
  4. Kurlon

    Kurlon Well-Known Member

    Your wideband isn't going to last very long with premix hitting it. :D
  5. mattology

    mattology Well-Known Member

    replacement sensors are like 70 bucks, i've been using them with leaded gas and what not for years. i bet they last as long as a piston ring does. i think the big one is warm the bike up without the wideband in, and then once its warmed up, install the wideband into the pipe.
  6. dave3593

    dave3593 What I know about opera I learned from Bugs Bunny

    On my TZ I battle that transition by not closing the throttle all the way and keeping very light pressure on the rear brake.

    Maybe someone already mentioned this but raising the idle speed will decrease this transition providing your carbs even have an idle setting.
  7. mattology

    mattology Well-Known Member

    thank you for the insight, dave
  8. dave3593

    dave3593 What I know about opera I learned from Bugs Bunny

    Two strlkes are cool but persnickety. ;)

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