Engine Trouble Seeking help engine wont turn over

Discussion in '2-Stroke Engines' started by scythyn, Apr 2, 2013.

  1. scythyn

    scythyn New Member

    I drive a 2 stroke mountain bike, i just bought three days ago. The motor was newish. it had been driven afew times. im not sure the distance.

    I took it for a ride the day i got it, not going fast just checking it out. i don't know much about bikes untill the last three days when it suddenly broke down on me.

    now the first day i drove it it was whicked. no stalls nothing. i did smell gas like mad though. didnt see any leaks.

    so the next day i took it out. decided to go for a long drive we will say about 25 kilometers. i probably reached speeds of 50 kilometers at times. I might have driven the bike too hard im not sure. But i stopped multiple times to let it cool down.

    i gunned it and went as fast as i could but not to the fullest. it had more potential it was just a small incline i was on. thats when she started to lose throttle. and giving it more did nothing for the engine. no acceration not nothing. she slowed down, still running and then died when it stopped. I could not get it to start up again.

    There was no pop from the engine turning, the back wheel was locking up a bit and i could really smell gas.

    I looked online for many things and the first thing they said to check was the spark plug.

    i took the plug out and noticed it was dark brown. I replaced it with a nkg b6hs but still cant turn the engine over to get a spark. i disconected the kill switch and rewired the magneto to the cdi leaving the white wire isolated.

    still nothing.

    i took the spark plug out and tried to pedal but it so hard and it makes a grinding noise. no engine popping. or putting.

    do you think maybe i have a flooded engine? maybe gas leaked out of the lines or the carb and went down into the pistons. maybe it seized. i dont know how do i check?

    when the clutch is released it dont budge. no engine turning.

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    You forgot to say this part of the story.

    seriously, asking the same questions here in lots of different threads
    isn't going to help much.

    Last edited: Apr 2, 2013
  3. scythyn

    scythyn New Member

    i tired all of that stuff i cant get the damn engine to turn over i think its hydrolocked
  4. scythyn

    scythyn New Member

    how can i check for spark if i cant turn the engine over? i cant even move the bike with the clutch released. only half released
  5. V 35

    V 35 Member

    Could be a lower end problem, you may be better off replacing engine, keep your old one for parts, sounds like a good top end .

    You'll probably have to tear down to find problem, if top end comes ' right ' off , it's probably OK . If jug is reluctant to slide off, your cylinder is seized, and bottom end may be OK . Bright side = inexpensive motor, old one for parts, dead parts to offer to gods of speed
  6. Fabian

    Fabian Well-Known Member

    The engine is f^%*ed

    You need to purchase a new engine - no amount of discussion will help fix the problem.
  7. swamprat

    swamprat New Member

    don't know if this will help but i once had a go kart with a 8hp honda and if i let it sit with the fuel shut off open the fuel would seep thru the carb and fill the crankcase locking up the motor.
    scythyn likes this.
  8. scythyn

    scythyn New Member

    how do i drain it it smells like gas like mad
  9. Anton

    Anton Administrator Staff Member

    I think your engine maybe seized. If you want to check unscrew the 4 large nuts on top of the engine. The head will slide off first (the part where the spark plug screws in). Then try to slide the barrel off and like V 35 said above it should come off easily. If it doesn't slide off easily refer to Fabians post above.
  10. scythyn

    scythyn New Member

    thank you i will do this. Should i remove the gas tank the engine is still on the bike
  11. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Seriously, scythyn has been making a lot of confused posts on the other
    forum and your advice will have him mess up his motor more.

    He didn't like or couldn't understand the answers over there so
    know he is trying here.

    I am not convinced his motor is seized.

    Before you take the head and barrel off.

    Remove the spark plug.

    Pull the clutch lever in or remove the chain.

    Remove the magneto cover where the wires to the CDI come out.

    Take a socket wrench and try turning the nut on the end of the
    crankshaft under the magneto cover.

    If you can turn that nut your motor is not seized and the
    piston will go up and down.

    This is a lot easier way to check and he won't break his rings.
  12. Anton

    Anton Administrator Staff Member

    Yep do what MotorBicycleRacing says first. My advice is only once you know the engine is definitely not turning over and you want to see what the actual damage is.
  13. scythyn

    scythyn New Member

    ok i will do that now i will let you know how it goes. im a newb to these bikes. i didnt look up anything on it before i drove it(not thinking excited about having one) and now im just learning
  14. scythyn

    scythyn New Member

    may i just explain i thought at first it might have been a wire problem. i was 25 kilometers away from home. i put the clutch in and locked the safty and pedaled home. took me hours. i tried to start it a few times but it just didnt turn over. so it started with me believing it could have been the engine. i didnt think about what it wa first so i posted on another fourm re explaining the problem
  15. scythyn

    scythyn New Member

    i did find a loose wire when i looked at the cdi and magneto connectiong. they had just been clamped. i just got my new magneto and cdi(just in case) so im going to turn the engine over with a socket wrench and see what happens ill get back on it
  16. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    What color was the loose wire?
    How old are you? :D

    take some pics of your motor and bike from a few different angles please.
  17. scythyn

    scythyn New Member

    ok so i took off the chain and turned he engine over with a socket wrench. i found that the nut holding the gear in place was loose so i took of the clutch side of the engine and unscrewed the flower nut and tried to tighten it. when tightning it back up i tried to put the pin back in and it wont go in
  18. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    you didn't follow simple instructions.

    making dozens of barely understandable posts all over 2 forums will
    not get your motor fixed.

    some people just aren't mechanically inclined enough to work on these
    crappy little engines.

    my advice is to sell your bike and motor for whatever you can get for it
    and buy a Japanese scooter.

    Good Luck! ;)
  19. V 35

    V 35 Member

    We all started ' somewhere ' I was lucky, first build ... new to gas bikes, but had 30 + years working on vehicles and power equipment,
    so welding, paint, electrics, all came naturally. YES these bikes are a * pain * until you get to know them. Cruising the forums will give you lots of advice, keep a notebook to write tips down, you'll get many, and they will be scattered

    Please be patient with us ' remote experts ' we can't see your machine, and can only logicly eliminate problems by guesswork, and past experience. If you wanted a scooter, you would have bought one. Don't give up, possibly start a second build, using experience gained from first one. I'll never forget my first ride, from one end of my parking lot to the other, what a bummer ! Took some tuning and patience, but got it to run well enough to know how bad it sucked. My second build had the virtues, but not the vices, was easy to do, and ran well.
  20. Fabian

    Fabian Well-Known Member

    Although they are a basic design, these engines can be a serious pain in the backside when they want to misbehave and play mind games with your head.

    Sometimes it's just more efficient to start the day all over again with a new engine, especially if you are new to the game.