Trouble With First Start

Discussion in 'Motorized Bicycle Trouble Shooting' started by ninjaplatypus42, Jan 14, 2017.

  1. ninjaplatypus42

    ninjaplatypus42 New Member

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    I have a brand new engine with a centrifugal clutch, pull start, and shift kit. The pull start is because i can't turn the engine over pedaling because the shift kit gears down the power from pedaling so much. I also had to make a makeshift intake because the engine fits too high up on the frame. I made it from copper pipes jb welded together. It's a little longer (about 2 inches) than stock but they make extended intakes so i didn't think it would be an issue. I'm getting spark and gas it getting into the cylinder. I've pulled on the thing for about half an hour. I don't know how much pulling needs to be done to start it for the first time if anyone has a pull start that's done this before. Or if there's an actual issue with either the homemade intake or something else. Any help is appreciated, thanks!
     
  2. crassius

    crassius Well-Known Member

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    I'd first try a few drops of fuel thru plug hole before even starting to check gaskets and things.
     
  3. ninjaplatypus42

    ninjaplatypus42 New Member

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    Will try tomorrow. It's dark and raining at the moment. Florida hates bikes :p
     
  4. ninjaplatypus42

    ninjaplatypus42 New Member

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    Gas in the plug didnt work. I'm using 16:1 btw. There was a popping sound and some white smoke came out of the carb at one point before i tried the fuel in the plug. Not sure what that means.
     
  5. TheNecromancer13

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    Did you try setting the carb to the leanest setting? I've seen engines that wouldn't even start cause the carb was set so rich.
     
  6. Chaz

    Chaz Active Member

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    Your gas mix at 16:1 is very heavy. It's safe at 32:1 and may be much easier to start. Also try gapping the plug down to .022 inch
     
  7. ninjaplatypus42

    ninjaplatypus42 New Member

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    I'e tried in the middle, leanest and richest. I'll switch out the gas as well and try it again. I'm goin to get another plug anyways so ill change the gap on that one.
     
    #7 ninjaplatypus42, Jan 15, 2017
    Last edited: Jan 15, 2017
  8. crassius

    crassius Well-Known Member

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    no pop with fuel in hole often means bad plug or loose head gasket (carb & bottom end gasket aren't involved at that point)
     
  9. ninjaplatypus42

    ninjaplatypus42 New Member

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    The plug is sparking so ill tighten the head down as well.
     
  10. Tyler6357

    Tyler6357 Member

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    Yeah, don't tighten it too much. The head nuts should be torqued at about 15 foot pounds. Over tightening fasteners has caused more problems than any other one thing with these kits. In the case of the cylinder head too loose or too tight can cause you further problems. Use a torque wrench, if you don't have one, get one because you are going to want to check it often.

    brnot
     
  11. ninjaplatypus42

    ninjaplatypus42 New Member

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    I've got one. Just double checked to make sure it was the proper tightness. It was so on to other things.
     
  12. ninjaplatypus42

    ninjaplatypus42 New Member

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    I just checked it and it was right at 15 ftlbs. on to other things.
     
  13. crassius

    crassius Well-Known Member

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    a fouled plug can spark in air, but not under compression - you could try any plug that is not too long just for testing

    many auto parts stores will loan a compression tester for free to check that
     
  14. ninjaplatypus42

    ninjaplatypus42 New Member

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    Huh, didn't know that. I'll get a replacement then, they're only like 4 bucks so i'll just buy it outright.
     
  15. ninjaplatypus42

    ninjaplatypus42 New Member

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    Replaced the spark plug and switched the gas to 32:1. The head is properly tightened and there aren't any leaks elsewhere that i can see. Not sure what else to check at this point.
     
  16. TheNecromancer13

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    Are you using the acorn head nuts that came with it? They have a tendency to bottom out on the studs before they are actually tight. Try replacing them with normal nuts and re-tightening.
     
  17. crassius

    crassius Well-Known Member

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    I've got a thread somewhere here (probably under electrical) about making a timing mark to check CDI timing, but it is rare to get good spark at wrong time

    if someone is near you with a CDI to borrow, I usually just try one to eliminate that

    19 times out of 20, it is some really simple thing, but with all the changes you made, it may be hard to find, like if rotor was off to put in pull start, maybe it went back on backwards or without woodruff key or a lack of enough head stud washers so nuts are tight but head is too loose

    did you try a cold compression test?
     
  18. ninjaplatypus42

    ninjaplatypus42 New Member

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    The nuts are tight i checked that when i checked the torque. I have another bike so i can check the cdi with that one in a couple days. I'll double check to see if the rotor is on the right way but i am getting a spark which i wouldn't if that was backwards correct? Or would it just be mistimed? Definitely didn't forget the woodruf key I double checked that lol What is a cold compression test?
     
  19. TheNecromancer13

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    If you're using the stock acorn nuts, the nuts may be tight because they are bottoming out on the studs, instead of because they are holding the cylinder head in place.
     
  20. ninjaplatypus42

    ninjaplatypus42 New Member

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    I know I've checked that though. I took the lock washer and normal wassher off the stud and the nut almost touched the caseing so that's fine.
     

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