Rear tire and motor locked up

Discussion in '2-Stroke Engines' started by ayo2001, Oct 14, 2015.

  1. ayo2001

    ayo2001 Member

    hello, i'm new to the motorized bicycle world and i'm having a bit of trouble with my 80cc engine (Chinese engine unfortunately) I was on my way back to my house when all of a sudden the bike comes to a complete stop and the back wheel locks up. I also saw smoke coming out of the cylinder . So i tried to pedal and get the engine running again but nothing happens and its really hard to pedal when i pop the clutch. I'm not sure if the engine is seized or what but i know its not the chain getting bunched up. I can still move the bike freely when i disengage the clutch but if i try to get the engine started up it doesn't do anything, it doesn't turn over ,no kind of noise , nothing. Any idea what the problem might be?
     

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  2. crassius

    crassius Well-Known Member

    first, take out the spark plug & see if motor turns when you roll bike forward - if it does, then you might have nothing wrong except for a slipping clutch & the forum has info about adjusting cable & flower nut

    if motor still doesn't turn, you'll need to open drive cover & clutch cover so you can see where turning stops when you roll the bike - many times you'll find a bad or missing woodruff key in one of the shafts when this happens
     
  3. ayo2001

    ayo2001 Member

    ok the bike still rolls freely when i'm holding in the clutch and i can ride it like a normal bike, its just when i let go of the clutch it locks up and i can't pedal at all , but i'll check the drive cover and clutch cover
     
  4. butre

    butre Well-Known Member

    if it's not slipping clutch then it's time for a teardown.
     
  5. jaguar

    jaguar Well-Known Member

    it seized
     
  6. ayo2001

    ayo2001 Member

    i found the problem, after a semi-break down of the engine, i found that my piston was stuck and i had to tap it a little to get it loose. turns out that i didn't have enough oil in it for it to be properly lubricated to run correctly so thats why the piston got jammed. Could anyone recommend a good oil to gas ratio i should use. I was using about 20:1 but maybe thats not enough
     
  7. crassius

    crassius Well-Known Member

    I'd say 20:1 is plenty if that's what you're mixing. 6 1/2 ounces to a gal?

    Unless you tried to mix in the gas tank rather than in a can which could be well shaken, then lack of oil didn't cause the seize - I'd look for another reason, like maybe the piston or rings on backwards.
     
  8. ayo2001

    ayo2001 Member

    yes i did try to mix it in the gas tank, i'm not supposed to do that i take it?
     
  9. butre

    butre Well-Known Member

    if you do the procedure is to fill with fuel a quarter way, dump in the oil, shake the bike, fill the rest of the way, shake again.
     
  10. crassius

    crassius Well-Known Member

    that can be risky - I've seen a lot of guys end up with almost straight gas that way or sometimes with the carb bowl full of straight oil - better to mix in a can and get it well mixed
     
  11. ayo2001

    ayo2001 Member

    So for my tank (half a gallon tank) i should mix it in a can first? And should i use a bit more oil , i would rather have a little more oil than not enough, don't wanna starve my engine again
     
  12. butre

    butre Well-Known Member

    20:1 is already more than most people run. I personally run 50:1, but wouldn't recommend any less than 40:1 to most people
     
  13. crassius

    crassius Well-Known Member

    32:1 has worked for me this last 7 or 8 years & mixing a gallon at a time makes measuring easy

    NOTE: walmart sells a spout for $4 that goes nicely on one gal oil jugs or antifreeze jugs or trans fluid jugs which all work well for gas & aren't as difficult to pour out of as "approved" gas cans
     
  14. ayo2001

    ayo2001 Member

    I was just wondering about my fuel filter, when i put in a new tank of gas and oil i will see the oil sitting inside of the little fuel filter but after riding around for a little bit i don't see it in the fuel filter anymore .im asking because i just want to make sure oil is getting into my engine, is it supposed to do this?
     
  15. crassius

    crassius Well-Known Member

    most oil has a blue dye in it so you can tell how much oil is mixed with the gas - you should see that in your fuel line - if you see just oil, you're not doing it right - if you see nothing in the line, try pushing the tickler button on left side of carb while watching line
     
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