Engine Trouble probly a stupid question, engine running like garbage

Discussion in '2-Stroke Engines' started by megamotormagna, May 10, 2012.

  1. megamotormagna

    megamotormagna New Member

    While trying to figure out why in the **** my 80cc is running like garbage, i took the carb and intake off just to peak at the rings. when the piston is at the bottom of its stroke i wasnt able to see the top of the piston, and into the combustion chamber like i can looking in through the exhaust port. so the fuel is actually going under the piston, is that normal? sorry if this is a stupid question i couldnt find anything while searching. i did notice another port in the combustion chamber, so i was hoping that the fuel goes under the piston then gets pushed up through the 3rd port?

  2. Al.Fisherman

    Al.Fisherman Active Member

    The fuel mix is taken into crankcase and forced into the combustion chamber through transfer ports. Look at the picture of the cylinder base gasket. Inside the cylinder there are 4 ports, intake, exhaust and 2 transfer ports.

    Much like this.......

    Attached Files:

    Last edited: May 10, 2012
  3. megamotormagna

    megamotormagna New Member

    ok, good i had gotten alittle nervous lol. i think the problem im having is just the beginning of the downhill slide to the engines retirement =-(. i have read that people are reporting an average of 400-1000 miles before the end, and im alittle over 700 miles. i am now looking into just replacing the engine, or pricing out a complete rebuild. the problem is this is my only means of transportation to work. so i would have to be able to swap, or rebuild it on my weekend.
  4. Cavi Mike

    Cavi Mike Member

    If you're noticing a loss in power/performance, it very well may be your CDI, not the engine itself. If you've been kind to your engine by keeping the revs down and keeping to at least a 32:1 fuel/oil mix, the engine should be just fine. My last CDI got so weak I had to run a .015" spark-plug gap just to keep the thing running. A new CDI and a re-gap and it was running like new again.
  5. megamotormagna

    megamotormagna New Member

    To be honest im a bit of a speed demon, lol. Although id hit WOT i wouldn't hold it long just long enough to hit a top speed then back to 1/2 throttle for awhile, then up to WOT again. i have thought about the cdi and checked spark, it seemed weak kinda yellow color spark?
  6. wheelbender6

    wheelbender6 Well-Known Member

    Definitely not a dumb question. I used to have very difficult time understanding how increasing the height of a port in a two stroke was the equivalent of running a higher duration cam in a four stroke. Tough to visualize.
  7. megamotormagna

    megamotormagna New Member

    I have decided to go ahead and order a new cdi, bummer part is im still going to have to ride it to and from work until it gets fixed or detonates which ever comes first.