79cc pred 4 stroke Questions

Discussion in 'General Questions' started by WR010, Mar 30, 2015.

  1. WR010

    WR010 New Member

    1. Removed governor, do I need stronger springs due to higher rpms? Where do I get them if so?
    2. Carb and air filter- any notable upgrade recommendations would be appreciated.
    3. Tachometer- How can an analog/dial tach be installed on 79cc?


  2. KCvale

    KCvale Motorized Bicycle Vendor

    I have some pretty detailed pictures and explanations of how I did the throttle in this topic.

    Tach's are usually just a clip on the spark plug wire, or a coil around it.
  3. WR010

    WR010 New Member

    Thanks for response, funny I have your page saved already and I was going to change my set up like yours. I have 11T clutch, 10 Jack Input, 9 Jack Output on a 44T from old china kit. I believe I may be doing 12-14 mph, does this seem right? I order a 16T and 20T for Jack Input. Ratio says I currently have 4.44. Did you do any upgrade to Carb?
  4. darwin

    darwin Well-Known Member

    Ace hardware has an assortment of universal springs to choose from.
  5. KCvale

    KCvale Motorized Bicycle Vendor

    No, I didn't do any internal carb mods.
  6. infinity526

    infinity526 New Member

    I'm looking into doing a build like this soon, and that guide was pretty cool. Couple questions, if you don't mind. On one photo, you're pointing at a tab/handle on the right side with the caption "disengaged", what is the function of that piece? Second, with the governor removed, how do you keep from over-revving the motor and damaging it, just throttle control? What's your recommendation on maximum RPM?

  7. professor

    professor Active Member

    I have a 79 on bike number one, I opened the main jet a couple of thousandths, stock aircleaner, my exhaust, stock governor disconnected externally, still use the provided throttle attachment.
    The engine flattens out rpm wise around 5000.
  8. WR010

    WR010 New Member

    There's a tab on the carbs actuator that stops it from turning further, is this a governor too? What gears are you running?
  9. KCvale

    KCvale Motorized Bicycle Vendor

    These engines are typically used in generators, that is the manual throttle.
    That piece that goes into the engine is what makes the engine rev faster when under load.
    Just disconnect the linkage and you can fully control the carb by the handlebar throttle.

    ~5500 rpm is as far as you want to push it.