idle rpm question...

Discussion in '4-Stroke Engines' started by rockrtboy, Sep 1, 2015.

  1. rockrtboy

    rockrtboy New Member

    what does the 4 stroke hau sheng idle at? mine said 4000 that accurate on my tach?

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    2000 rpm so you have the tach on the wrong setting.

    Hey what tach do you have?

    7800 redline.
  3. rockrtboy

    rockrtboy New Member

  4. HeadSmess

    HeadSmess Well-Known Member

    just set it so it sounds right? if it stalls, too low, if the clutch is grabbing, too high, and if you cant quite find the in between point, you need to adjust the lowspeed mixture, which is that tiny lil screw on the side of the carb. you set the idle slightly high and twiddle that screw til it peaks... then back off a touch. then readjust the idle and check... tweak if required.

    learn NOT to rely on silly electronic gizmos that can send you off on tangents... these are not auto engines with sophisticated ecu and efi and all these other silly electronic things that can only be checked by plugging into a 10k+ machine and have to be kept within guidelines set by the EPA.

    (yeah...real sophisticated...most of em still run basic led flash diagnostic systems... akin to the beeps your pc makes when somethings gone wrong... akin to using a pc in the early 70's... but its "bulletproof". they dont need to be user friendly, just to WORK.)

    say, an oscilloscope is great, but my friends one kept producing a waveform he liked...he fiddled with a circuit for weeks, scope said it was working, but it ended up being the scope itself that was the problem.

    same deal with his component tester. gave him the wrong pinout on an scr and it wasnt until i came and googled it for him that he realized why it kept emitting brown smoke... great on the majority of things but when you REALLY need it, its lets you down.

    multimeters etc...unless you fork out big dollars they give spurious readings that can really drive you nuts. i refuse to use those stupid "auto-ranging" ones, they really are just a gimmick.
  5. KCvale

    KCvale Motorized Bicycle Vendor

    I have used that one.


    Set at 2 stroke as the mag fires every turn even though only every other turn produces a compression spark.


    I liked that Hour/RPM unit myself.
    Like most things these days it has a built in fail time, ~a year and you can't just change the battery.

    ~2300 rpm idle seemed to work well.
    It's the hour meter that is cool.
    Change the break in oil at 10 hours, then every 50 hours with good stuff.