Exhaust How to tell if you blew a gasket and SPARKS on exhaust?

Discussion in '2-Stroke Engines' started by slaquers, May 12, 2010.

  1. slaquers

    slaquers Member

    I was running my brand new motor and noticed its smoking from the engine somewhere, is this normal also the exhaust sparks, like the actual tube of the exhaust sparks...ground issue or what? So confused I know nothing of these little 2 strokes 66cc's (Skyhawk GT5)

    Thanks in advance for helpin a worried noob!!

  2. Al.Fisherman

    Al.Fisherman Active Member

    If it's a painted engine, I don't doubt it might smoke for awhile (crappy paint), mine did. Can you see any tattle tale traces of oil on the engine, it will look black, might be that. As far as exhaust...grounding has nothing to do with it. I suspect that with the hot gases (Exhaust) that it might be burning some material left over from production. Gets hot and when it exits the pipe it looks like sparks. If you took steel wool heated it and forced air on it you'd have the same results.

    Your title mentions "How to tell if you blew a gasket" but nothing in the body. The only gasket you can "blow" is the head gasket. To check, either take a compression test or remove head and visually inspect it. The other gaskets can get burned out or disintegrate.
    Last edited: May 14, 2010
  3. vincevandal

    vincevandal New Member

    Nice, I'm having similar symptoms. This puts me at ease.
  4. motorpsycho

    motorpsycho Active Member

    9 times out of 10, a new engine will smoke when first started (smoke externally0.
    this is because the engines are covered in a light film of machine oil to protect them while they sit waiting to be shipped.
    If you are getting sparks out of your exhaust, it could be loose material in the pipe that is falling off when it gets good & hot.
    This is not uncommon because the chinese welding process isn't as good, and there will be lots of slag (debris) left over from the welding.
    If the sparks are coming from your exhaust externally, it can be the same thing...welding slag.
    but if your pipe is getting that hot, you may have a fuel-air ratio problem..running too lean.
    but since you don't know anything about these engines, that may be too in depth right now.
    you are mixing 2 stroke oil into your gas at a ratio of 16:1 or 20:1 right?
  5. I just dropped a 80cc on my bike New Mixed mine 50:1 just to be safe...I must be having a to rich or you say to lean if she has sparks coming out????

    Id like to know whats up with these sparks..It was just a open header it pretty broke in 2 tanks and still some sparks so is this getting too hot and need to be lean more or should I rich en it up?I'm almost sure I don't have any air leaks

    Scaring me..:sweatdrop:
  6. jaguar

    jaguar Well-Known Member

    What do you mean the exhaust tube sparks? like sparks from a campfire or electrical sparks?
    where are the sparks at?
    common for the head/cylinder mating surface to be uneven which allows more oil to seep out and wind up smoking if you are running hot. Plane them on sandpaper on glass.
  7. I had a intake manifold on in so i could slip my pipe on and took it out and it had a few sparks fly out when you gas it up,mill the head first ay?
  8. Fabian

    Fabian Well-Known Member

    What is the ratio that you normally would want to mix your oil/fuel ratio? 60:1, 70:1, 80:1, 100:1 ???
  9. I mixxed this at 60:1 fresh engine.
  10. Fabian

    Fabian Well-Known Member

    60:1 :ee2k:

    Is that a wise choice?

    for any air cooled engine, especially for a bottom of the barrel Chinese air cooled engine with poor metallurgy and unstable thermal dimensionality?
  11. heXed

    heXed New Member

    Slaquer, I just want to point out that the higher number in the ratio indicates less oil in the mixture, not more. At 50:1 or 60:1, your engine is getting very little oil to lubricate the moving parts.. more friction.. more heat.. likely it will not last very long. I run mine at 25:1 with good success, though others running a bit higher or lower than that. When reading the ratio, 50:1 represents 50 parts of gas to 1 part of oil... 25:1 would be 25 parts gas to 1 part oil or 50 parts gas to 2 parts oil. I would say you are using about half the oil you need in the engine. Hope this helps.
  12. Fabian

    Fabian Well-Known Member

    I also run mine at 25:1 with good success.
    25:1 seems to be the magic number to squeeze longevity out of these 2-stroke Chinese bicycle engines, when running higher duty cycle.

    I have run 35:1 but there was a noticeable reduction in the life of the cylinder bore and piston rings.

    If you are just putt-putting around; operating the engine at low duty cycle, you can get away with 50:1 but the jetting would want to be optimal, otherwise you'll tear up the cylinder bore and rings.
  13. HeadSmess

    HeadSmess Well-Known Member

    one jerry can, one mix, 50:1. chainsaw, pole saw, china bikes, hell, i even top up the 4stroke lawnmower and brushcutter with it! even the 650 gets the occasional splash when i know the servo is out of range.

    i dont putt-putt around, either. 2 hours at WOT is a low duty cycle ONLY if you consider it might sit next to the shed for a week or more at a time between runs.

    what kills my engines? over doing modifications, blown crank seals, and piston ring locating pins. no oil on earth will prevent that from happening.

    and lending them to people that have a habit of forgetting oil altogether...