Idle speed/tachometer

Discussion in '2-Stroke Engines' started by Comandoriv, Apr 10, 2016.

  1. Comandoriv

    Comandoriv New Member

    Hi everyone,

    I couldn't find an answer to this using the search function.i had just installed a tachometer to the bike and I was wondering what the ideal idle speed would be?

    Currently its at 1350 rpm. Would that be too low? Thanks!!

  2. KCvale

    KCvale Motorized Bicycle Vendor

    Too low and it dies, that's it, no special number.
    Now what are you using for a Tach?
    There are many and it has be set right for 2-stroke engines.
  3. Comandoriv

    Comandoriv New Member

    I'm more used to 4 strokes in terms of necessary idle speeds. I only figured that too high an idle could cause overheating. So I figure a few hundred rpms above where it dies works.

    Im currently using

    It's different from the aftermarket tachometer that I put on my motorcycle that hooks to a negative coil cable. This one literally just wraps around the spark plug wire and uses induced magnetism to read rpms. It is set up correctly.
  4. Hello Moto!

    Hello Moto! Active Member

    I set my idle on the slower side. I just listen for what sounds right to me and keeps the engine running. The only problem I ever had with idling issues was when I used a boost bottle. I just couldn't get sh*t to jive with that thing on there so I don't use it.
  5. butre

    butre Well-Known Member

    I just set my idle as low as it'll go and consistently stay running. I've got a thumb screw on my idle adjustment so I can mess with it on the fly
  6. Comandoriv

    Comandoriv New Member

    Thanks guys! I'll just take it as idle as slow as possible without engine stalling.

    Still new to 2 strokes, as with 4 strokes too low an idle can starve top ends of oil. But 2 strokes with oil in the fuel I'm assuming there is nothing to be starved of oil.

    Good to knw about the boost bottle too.
  7. KCvale

    KCvale Motorized Bicycle Vendor

    That what I use too.

    When the engine is off it displays total hours, when on it shows engine RPM's.
    Note than on a 2-stroke the engine output has an internal gear reduction so you can't use that number to calculate gear ratios.

    For mount on a bike they are not a friendly design, mount well on the goose neck with some long bolts and fabricated bracket.


    For ~$15 a cool little instrument, especially for 4-stokes, you can set a 'maintenance interval' to let you know when it's time to change your oil.
  8. Comandoriv

    Comandoriv New Member

    I agree it's definitely not a friendly design. I just mounted with longer zip ties.

    My bike isn't put together in any professional or good looking way. Just a solid way that works and mainly used for single track dirt trails. I guess thats how "most" first builds go? Haha

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