Engine wont turn now

Discussion in 'Motorized Bicycle General Discussion' started by kfree, Aug 21, 2013.

  1. kfree

    kfree New Member

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    So my new 2 cycle was running just fine until I flipped the choke and it died. Since, it wont start and it seems like the engine is not turning (i.e. no compression) when I let out the clutch. Any thoughts?:-||
     
  2. dumpstercrusher

    dumpstercrusher New Member

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    flip the choke back? lol
     
  3. dodge dude94

    dodge dude94 New Member

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    Too much fuel it sounds to me.
     
  4. crassius

    crassius Well-Known Member

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    could you have dripped fuel into the clutch making it slip?
     
  5. mew905

    mew905 New Member

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    engine wont turn at all, no compression. Can the wheel still turn freely? If so, it's a clutch issue. Perhaps you have a seal leak in the gear case and it's sprayed onto the clutch pads (I got lucky and mine simply lubricates the gears :p ) Or maybe you sheared a key (unlikely, but possible)

    If the wheel doesn't turn freely and it takes a ton of force to spin, but the motor STILL wont turn over, then you have a bigger issue: seizure. Whether it be the cylinder or something got caught and jammed somewhere, it may require a complete teardown.
     
  6. mrfubs

    mrfubs New Member

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    You need to be 100% sure if the engine does not turn over. Take the magneto cover off and watch to see if the magnet moves at all wile you disengage the clutch.

    If the magnet does not move then you probably broke a piston ring right at that moment you flipped the choke and got caught in a port or some how managed to sheer the magnet key.

    Its a step by step process to diagnose.
     
    #6 mrfubs, Aug 21, 2013
    Last edited: Aug 21, 2013
  7. dodge dude94

    dodge dude94 New Member

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    You could always just pull the head and see what's going on...these engines aren't really rocket science when it comes to tearing them down...
     
  8. mapbike

    mapbike Active Member

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    I'm assuming when you say flipped the choke you mean that you lifted the choke lever up and then it died, if that is what you did then you probably just flooded the engine with an extra amount of fuel and possibly fuel fouled the spark plug.

    Heres the part that is a bit confusing to understand (it wont start and it seems like the engine is not turning (i.e. no compression) when I let out the clutch.)

    If you get on bike, pull in on clutch lever, pedal bike up to a few MPH and then release the clutch, does the engine turn over as it would if you are trying to start the engine but just wont start up and run?

    OR, when you follow the above steps does the engine just lock the rear wheel up when you release the clutch lever?

    OR, does the engine spin/turn over but does it just spin very easily as if there is no compression just like as if you had removed the spark plug?

    Really need to narrow some things down here before I can point you in any direction, several opinions here posted already, but without clearing up some things and knowing exactly what you are doing and exactly what the engine is doing its just wild guessing that could be way off in left field.

    look over what I said here and give me you best shot at which of the things I described is what you have going on with the engine.

    Personally I think it should be something real simple, but that isn't always the case.

    Peace, Map
     
    #8 mapbike, Aug 22, 2013
    Last edited: Aug 22, 2013
  9. kfree

    kfree New Member

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    I pulled the head and rocked the bike back and forth and noted the piston was frozen so I sprayed some wd40. I rocked it again and it moves freely now.

    With the spark plug out the motor turns freely when I let out the clutch. With the plug in, it doesn't seems to turn at all.

    Any thoughts? Thanks in advance.
     
  10. mew905

    mew905 New Member

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    If the plug is stopping it from moving, it's just compression, and is normal. When you pulled the head the piston may take the jug with it, it is a tight fit, however holding the jug down would be more than enough force to allow the piston to slide up and down. If the piston is seized, then it wont move at all, I dont know how people have replaced the top end in this case, but I dont think that's you're issue. If the piston was jammed in the cylinder, you may not have enough oil in your gas, or you may be running too lean.
     
  11. kfree

    kfree New Member

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    It's no longer seized. It moves freely with the plug removed. But if the compression is so high that the engine won't turn, then it certainly won't fire up, right?
     
  12. CTripps

    CTripps Active Member

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    When I built my cruiser, it was a bit like that.. without the plug the motor would turn and I could smell fuel puffing out of the plug hole, but with the plug in and tight it fought against turning over. Fortunately I live on a hillside, so I walked it up to the end of the lane behind the house, pointed it down hill and started rolling. Left a couple of skid marks on the hill from the first two tries, but turned over and fired right up on the third try where the ground levels out behind the house.
     
  13. nightcruiser

    nightcruiser New Member

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    Sounds like your clutch might not be engaging enough to make the motor turn over while under compression? If the piston is moving when the plug is out but when you put the plug in and release the clutch the motor doesn't turn (and the back tire doesn't lock up and skid) then your clutch is slipping. It SHOULD lock up and skid if the motor were to be seized or having too much compression....

    If this is the case, your clutch being the problem, then you need to check the stuff others posted about the clutch. Make sure the lever is releasing the clutch all the way (Pull the cable off the clutch arm, does the wheel lock now?) If there is slack in the cable and turning the wheel still doesn't turn over the motor (or lock the tire) then you have an internal clutch problem. Grease/oil on the pads? Something coming loose in there? Tighten the flower nut?

    If the clutch isn't greasy or something loose, then adjust the flower nut to make the clutch grab better. To do this, remove the screw on the flower nut, LOCK THE CLUTCH LEVER IN (which takes the pressure off the flower nut) then turn the flower nut in a little at a time until when you release the clutch it grabs firmly....

    Good luck!
     
  14. crassius

    crassius Well-Known Member

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    how about a list of all things that have changed since it ran well
     
  15. mrfubs

    mrfubs New Member

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    If the engine doesn't turn over with spark plug in make sure the tip of the spark plug isnt getting hit by the piston on the compression stoke. A easy way to check this is to put the spark plug in the head and put the head on the engine all the way on with out putting the acorn nuts on. Slowly turn the engine over and see if the head lifts off the cylinder at all , if it does than the plug threads are too long. If you have the original plug and head you should not have this problem.

    Did any of the cylinder wall plating flake off from the piston seizure? What oil ratio are you running too?
     
    #15 mrfubs, Aug 24, 2013
    Last edited: Aug 24, 2013
  16. kfree

    kfree New Member

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    I spent a couple of hours wearing myself out and banging my head against a wall to get this thing started over the weekend without success.

    I adjusted the clutch and cable for maximum engagement. I also degreased the inside of the clutch to rule out slipping. The clutch is most definitely grabbing hard (which is why I wore myself out). I have made no mods to the kit (all original) and it ran great right out of the box.

    I can tell there is spark and fuel and none of the ports appear to be clogged and, if I remove the plug, the piston moves up and down easily when I release the clutch lever so its not seized.

    laff
     
  17. crassius

    crassius Well-Known Member

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    open the magneto cover and make sure the engine is turning with the spark plug in
     
  18. dodge dude94

    dodge dude94 New Member

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    Any abrasions on your piston? You might take a dry erase marker and make a small circle on your piston in about the same area where the plug would be located, and see if it's disturbed by the spark plug.
     
  19. mapbike

    mapbike Active Member

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    If you have Fuel, Good Compression, Spark at CORRECT timing, the engine will at least try to start unless it is getting way to much fuel and just fuel fouling the plug.

    Sounds to me you have overlooked something very simple probably or you've had a failure somewhere, possible sheared crank key, which has the timing all wrong, if you have fuel, compression and spark it will at least try to start unless timing is off.

    best wishes, dont give up.

    Map
     

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