Engine Trouble 2 stroke 80cc motorized bicycle question!

Discussion in '2-Stroke Engines' started by ryansclzo, Aug 16, 2012.

  1. ryansclzo

    ryansclzo Member

    Hello, I have a question about my motorized bicycle:

    Every time I start it up, the engine will turn off every time I go uphill or just stop... is it supposed to do that or is the engine still supposed to be running unless I pull the throttle? I've only ridden mine about a mile so far and am wondering if ill ever be able to just let the engine run if I need to stop for a second at like a stop sign and wont have to redo the clutch/pedal more.

    Maybe that only happens with 4 strokes?

    Any advise will be appreciated :). Happy MB'ing
     

  2. adrian101

    adrian101 Member

    If you don't hold in the clutch at a stop sign or while at a complete stop the engine will stop. (Stall), When coming to a complete stop it is necessary with these engine to pedal until enough speed is gained to release the clutch and for the engine to start.

    What your thinking about is with a 4 stroke where a clutch will engage and disengage itself when throttle is applied.
     
  3. ryansclzo

    ryansclzo Member

    I'm not sure you understood what I was trying to say lol, I meant my engine won't stay running if I ever stop :S. Even if im holding throttle down, the engine will stop if im going uphill. The only way to keep the engine going while im riding is to keep pulling throttle
     
  4. timtooth

    timtooth Member

    You try adjusting the idle, an you might want check to see if your slider is moving freely.
    Which carb do you have?
     
  5. ryansclzo

    ryansclzo Member

    i have the stock carb from chinese kit.... the cylinder inside the carb isnt going inside it and idk why... when i pull throttle i see the end of the cord go out but not the cylinder
     
  6. timtooth

    timtooth Member

    Sounds like it getting stuck, take it apart use piece of sandpaper to remove
    the burrs off your slider to get it to move freely.
     
  7. ryansclzo

    ryansclzo Member

    I've got it working now but I have no idea how to work the choke, the bike keeps ticking and my engine ticks too as im riding. I'll video record the sounds while im riding brb.
     
  8. ryansclzo

    ryansclzo Member

  9. motorpsycho

    motorpsycho Active Member

    sounds like your choke is closed all the time.
    the choke is the little lever on the right side of the carb.
    lift the choke lever to start a cold engine.
    once it's running, lower the choke lever to open the choke.
    if the choke is left closed, your engine will not run once it's warmed up.

    holy cow...you have a lot of loops in your cables!
    it's possible that your throttle cable is bound up and not moving all the way.

    are you sure that you have the slide inserted in the carb the correct way?
    it can go into the carb 2 different ways, but only one way is correct.
    the slide is the round barrel looking thing that slides down into the carb that has the throttle cable hooked to it.
    remove the top cap on the carb and pull the assembly out (slide, spring, needle and cable).
    look at the slide and you will see that it has 2 slots in it at the bottom. you should see a long slot and a short slot.
    make sure that the long slot is on the right side of the carb(when looking at it from above). the long slot in the slide has to line up with a pin that's on the inside wall of the carb. the short slot goes to the left side and lines up with the idle screw.
    if you have the slide in backwards (long slot to the left, short slot to the right), your slide will stick, won't give you any throttle response and you will not be able to adjust your idle with the idle screw.

    you could have one of these things going on, or both.
     
  10. adrian101

    adrian101 Member

    After watching the video i believe this is the problem. Also you should check to see if the fuel is flowing correctly. Sometimes a airlock will stop the flow of the fuel and cause it to do what happened in the video.
     
  11. adrian101

    adrian101 Member

    by the way, to test if it a fuel flow problem, take the cap off the gas tank. then ride it like you normally do.. don't do it if your tank is full for obvious reasons. If it doesn't cut out after riding it like you normally do you know it is a fuel flow problem. but also check your choke.
     
  12. ryansclzo

    ryansclzo Member

    thank you all for trying to figure out whats wrong with it :). The bike only is good when the choke is about a half inch not closed. It runs fine when its like that. If I close the choke, the bike will stop when running. I went for a 2 mile and a back ride yesterday and when I was coming back my whole chain came off lol.... Im lucky because nothing bad happened. When I stopped I noticed my chain tensioner was gone and that was the problem. I found the chain 20 ft behind me and could not find the tensioner pulley thing. When my tensioner is not on the chain is wayy too loose. So I know what happened. I ordered a new tensioner and it will come thursday.
     
  13. Fabian

    Fabian Well-Known Member

    Maybe you should look at getting a SickBikeParts shift kit, to eliminate the single speed drive chain issue.
    At the end of the day a single speed system is a compromised drive method.
     
  14. motorpsycho

    motorpsycho Active Member

    Well, if it only runs with the choke partially closed, that tells me that you have an air leak either at the intake manifold to cylinder gasket or where the carb clamps to the intake manifold.
    your engine should die if you close the choke once the engine is warmed up. once its warmed up the choke soul be opened all the way. if it dies, its getting too much air, which indicates an air leak.
     
  15. motorpsycho

    motorpsycho Active Member

    The kit chain tensioners are junk & aftermarket ones are expensive. you should shorten your chain by removing links so you don't have to fight with a molding chain.
    you can run it without a tensioner, but the chain adjustment has to be perfect.
    a shift kit will take the tensioner out of the equation, but a shift kit will set you back about $250.00. I don't know about you, but that's more then I have in both of my bikes individually.
     
  16. motorpsycho

    motorpsycho Active Member

    Removing the gas cap is good advice. sometimes the vents in these gas caps are mo good and if the tank isn't vented, it will cause a vacuum in the tank & it will stop fuel flow into the carb. if it runs good with the gas cap off, you'll have to dry a small hole in the gas cap to allow it to vent.
     
  17. Fabian

    Fabian Well-Known Member

    $250 for dependable reliability. That's a bargain not to be missed out on.
     
  18. luis308

    luis308 New Member

    Hey i have the same problem with my 80cc bike it doesnt stay on when i make a full stop i have to keep idleing for it to stay on. I need help with this what can it be? What do i do? Please help
     
  19. luis308

    luis308 New Member

    Hey i have the same problem with my 80cc bike it doesnt stay on when i make a full stop i have to keep idleing for it to stay on. I need help with this what can it be? What do i do? Please help
     
  20. crassius

    crassius Well-Known Member

    If you have adjusted your idle screw correctly, then it is probably your clutch dragging - search the board for complete instructions for adjusting the clutch.
     
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