80cc Happy time 22mph lull?

Discussion in '2-Stroke Engines' started by solitus3989, Jun 1, 2009.

  1. solitus3989

    solitus3989 Member

    Hi! I have the 80cc(67.5cc) Happy time chinese engine.

    I installed it last year, and it has been working just fine so far. I used to be able to cruise very nicely at about 25mph, and if i really cranked it i could reach 28mph but it was really screaming. now, with the throttle wide open, i can only reach 22mph. It seems to lull forward and backward (more speed, less speed) between maybe 22-23mph or 21-22mph.

    I recently discovered a break in the little cardboard gasket on the bottom of the engine, and my dad and i RTV'd it and it worked just fine (28mph).

    My thought is that it is running too rich or too lean. any suggestions?

    Does it have something to do with the weather finally heating up here in Wisconsin?



  2. pdxrhett

    pdxrhett Member

    As air cools, it condenses, therefore more oxygen is going in the engine. As air heats, less oxygen gets in the engine (cold air intake = more horsepower on a car).

    So, a loss of power is normal in this situation. If it is bogging down at full throttle (like too much gas), then adjust for more air flow in the carb
  3. Skyliner70cc

    Skyliner70cc Active Member

    and just how do you adjust to increase airflow in the carb?
  4. pdxrhett

    pdxrhett Member

    My air filter has a spone ring, then a little box type thing with holes around it goes over that. to give more air, i just put more holes in the box
  5. boogerballs

    boogerballs Member

    Try removing your muffler and start your engine. Don't run it for more than a minute, but that should be long enough to see if your muffler is clogged. If the muffler clogs up your bike will lose power like you describe.
  6. solitus3989

    solitus3989 Member

    Im going home in a few hours (about 5 hours, 2 hour drive) so i will try removing the muffler tonight and will repost with my results.
  7. solitus3989

    solitus3989 Member

  8. Hawaii_Ed

    Hawaii_Ed Member

    Looks leaky! Hope sealing it up helps it out!
  9. solitus3989

    solitus3989 Member

    yup! Im guessing that's the problem... lol

    When i ride, i can feel hot air hitting my left leg, where that break in the gasket is. Then, upon inspecting my leg, there is a nice brown goo all over where the hot air was hitting. It already happened once, but i thought i fixed it. i guess im just going to order a new gasket online at zoombicycles.com, unless there is a gasket at fleet farm or ace hardware that would work?

    Im all about cheap alternatives.
  10. Hawaii_Ed

    Hawaii_Ed Member

    Check on the forums, I know some have deleted the base gasket and just used like high-temp copper RTV. I did that on mine when it went and seems fine so far. I guess it also drops the jug down and raises compression just a bit.