2nd tank of gas, bike wont start

Discussion in '2 Stroke Bicycle Engines & Kits' started by kayosdad, Dec 25, 2016.

  1. kayosdad

    kayosdad New Member

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    80/60cc Flying Horse - brand new bike. Complete newb. The bike was a christmas gift to my 15 yr old son.
    Thefirst tank of gas was at the break-in oil/gas mix ratio. Filled tank from same gas can. Have not been able to start the bike since that 2nd fill up.

    Issue seems to be fuel flow. Petcock open, fuel attached to carburetor and fuel will not flow. I remove the line from the carb and the fuel runs fine into a gas can.

    Any help would be appreciated.
     
  2. crassius

    crassius Well-Known Member

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    first thing is to turn off petcock, take out drain screw on bottom of carb just above clutch cable - a bit of fuel should run out - now turn on petcock and see if fuel starts running out again

    if fuel is ok, check for spark, then look for things that may have come loose - wires, carb, head bolts
     
  3. kayosdad

    kayosdad New Member

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    Thanks for the quick reply.

    I drained the carb. Fuel flow returned for a moment and then stopped. Without
    the engine turning over how much fuel should be in the fuel line? Should it be full? Right now its about 1/4 full

    Thoughts?
     
  4. crassius

    crassius Well-Known Member

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    fuel line often has air in it - if fuel doesn't flow out with drain open and petcock on, but flows out end of line when it is off carb, then your float is stuck, or set too high, or has debris in the float valve
     
  5. kayosdad

    kayosdad New Member

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    took the carb apart. float was not stuck, no debris in the bowl, not sure how to determine if the float is set too high or not.

    Everything is tight.

    also not sure how to check for spark.

    Sorry for the very basic questions.
     
  6. crassius

    crassius Well-Known Member

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    as a rule of thumb, hold carb upside down with float on the tabs - sight across top of float - you should see the main jet just peeking up a bit through the hole in the float
     
  7. kayosdad

    kayosdad New Member

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    I must be missing something because there is nothing to adjust in the bowl or with the float.

    Just curious as to why it would have run fine on the first tank of gas and now I cant get it started
     
  8. crassius

    crassius Well-Known Member

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    that's OK if it looks like the right height, but if it is off a bit, you would slightly bend the two brass tabs equally to adjust it

    if no brass tabs, then you don't have the standard carb & we'll need a pic
     
  9. kayosdad

    kayosdad New Member

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    ok brass tabs just like you said. made the adjustment...still nothing.

    there is spark.

    clutch is working.

    kill switch disconnected.

    :-||

    I think I am running out of steam. Any further thoughts? I really appreciate the time you have already given me.
     
  10. Tyler6357

    Tyler6357 Member

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    To check for spark: (1) remove spark plug, (2) hook up spark plug boot to the spark plug , (3) hold the spark plug threads against the head metal to create a ground, (4) crank the engine by cranking the pedals with clutch engaged (clutch handle released) (5) look for spark. You might have to do it in the shade to see the spark.
     
    #10 Tyler6357, Dec 28, 2016
    Last edited: Dec 28, 2016
  11. Tyler6357

    Tyler6357 Member

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    What ratio of oil mix are you using? 16x1 is too rich, use closer to 20-25x1 for break in period. Make sure you are using a high quality semi synthetic 2 cycle oil. Also, you might be losing compression, check for air leaks, the most common spots for leaks are carb/intake connection, intake/intake manifold connection, head gasket/head connection, exhaust/exhaust manifold connection. Start with the basics, to get the engine to start you need (1) fuel (2) spark (3) compression. It sounds like a carb problem to me but maybe not. Are you using an NT carb? Is the spark plug wet or dry after attempting to start it?
     
    #11 Tyler6357, Dec 28, 2016
    Last edited: Dec 28, 2016
  12. crassius

    crassius Well-Known Member

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    next step is to see if plug is wet - if dry, then a few drops of fuel in cylinder and replace plug should get you a few pops out of the motor

    if plug is wet, it may be bad plug or a compression loss at one of the gaskets, or clogged muffler
     
  13. kayosdad

    kayosdad New Member

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    Ratio is 16 to 1 - recommendation from gasbike.net where the kit was purchased. Is there a good way to "clean" this incorrect ratio gas out of the engine?

    Plug is wet.

    I noticed today that there was some debris and fuel residue under where the exhaust attaches. I took the muffler off and it looks like the exhaust gasket is shot.

    This exhaust gasket is recommended in other threads - http://www.sickbikeparts.com/catalo...ducts_id=90&osCsid=hnrs0lgm5gn0ai67a1pcaoark7

    The head gasket appears intact but has paint on it. Not sure if that would make a difference or not

    It is an NT Carb.

    going to replace the gasket and plug. Other thoughts?
     
  14. crassius

    crassius Well-Known Member

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    starting the motor with exhaust loose is how to test for clogged exhaust - it won't keep it from starting

    if plug seems really wet, your motor may have gotten full of fuel from leaving petcock turned on when bike was parked
     
    #14 crassius, Dec 30, 2016
    Last edited: Dec 31, 2016
  15. Agreen

    Agreen New Member

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    I've found that if the spark plug is wet, you can dry it thoroughly and it will restart. I like to use brake cleaner to get the gas/oil mix off the plug, then let it fully dry. I mean FULLY. The inside of the plug (up where the ceramic is) has to be dry too. You can also use rubbing alcohol.
     
  16. Tyler6357

    Tyler6357 Member

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    16x1 is too much oil, it will just gunk things up if you use that much oil, I know they recommend 16x1 but everyone agrees that is too much, go 20-25x1 to break it in then switch to 32x1 after burning through several tanks. No need to clean out excess oil, however it sounds like it might be flooding. Try tuning carb. You might want to try a new spark plug too, even if it's good it's always good to have a spare one anyway.
     
  17. ragdolldude

    ragdolldude Member

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    Is your gas cap vented? If it's vent is plugged with dirt, or no vet, fuel won't flow very much.
     
  18. kayosdad

    kayosdad New Member

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    new Carburetor, New plug, replaced blown exhaust gasket, cleaned out gas tank, new gas mix at 25:1

    No difference. Will not start

    Not sure if this matters or not, but the temp outside was 29F when attempted to start

    This was supposed to have been a Christmas gift for my 15 year old. Needless to say Christmas was not what it could have been. Now I am just whining.

    Any other thoughts?
     
  19. Tyler6357

    Tyler6357 Member

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    If the head gasket blew it usually means that it either got too hot or it was missing (4 stroking). Is the head leaking air? If you have an air leak at the head gasket it won't start or if it's just a minor leak it will start but lose all it's power because of the loss of compression. Try shining a flash light on the side of the head/head gasket connection and see if you can see any light shining through from the other side. Go around the entire thing and look closely for any possible air leaks. Sometimes stock heads from China are not built very well and are not flat enough or they have a curve in them which doesn't let the head sit flat. If you blow the head gasket sometimes it will damage the ridge of the head that joins with the cylinder. Take the head off and look closely at the round raised ridge that connects to the head gasket. If you discover an air leak you will probably just get a new head (less than $10 for another stock one, high compression ones like a Fred-Head cost more but cool the engine better). However, sometimes it's the cylinder that is not flat enough and must be replaced or sanded down to make a flat surface, use a flat surface, like a piece of glass, to sand it to make it flat or you can get a new cylinder.

    http://www.ebay.com/itm/Cylinder-Sl...ash=item33abbc2b87:g:QhwAAOSwwbdWL4SS&vxp=mtr

    http://www.ebay.com/itm/MOTORIZED-B...ash=item3f5f01b015:g:sHMAAOSws4JW7H8r&vxp=mtr

    If you don't find a leak at the head it must be something else. Other possibilities are: damaged piston, a carb jet that is too big and flooding it, a broken ring, carb needs to be tuned properly, air leak somewhere else, no spark, timing adjustment, clutch slipping.
     
    #19 Tyler6357, Jan 5, 2017
    Last edited: Jan 5, 2017
  20. kayosdad

    kayosdad New Member

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    Took the top end off. Everything seems to be fine. Only problem is I have no idea what I am looking at. The only thing that seemed off was debris was everywhere. Like a mixture of sand and rubber.

    What should I be looking for on the piston? In the cylinder?
     

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