Brand New Chinese 66cc kit won't start. No spark(?)

Discussion in '2-Stroke Engines' started by ChupaBaby, Jul 5, 2015.

  1. ChupaBaby

    ChupaBaby New Member

    Hi,

    i bought a brand new generic Chinese motorized bike kit off eBay the other day. It's a 66(80cc) kit with a slant head. After installing it I couldn't get it to start. I'm sure it's getting fuel because the plug is wet when I pull it out. I've checked for spark multiple times and I only SOMETIMES got a spark ( like 2/20 times).However I still couldn't get it to start. I've tried adjusting the clutch but I'm positive it is engaging and the engine is turning over when I am trying to start it. I've also checked all my wires from the magneto to the plug cap. I recently replaced the spark plug with a NGK H6BS one and replacing the spark plug wire but I am still not getting spark. However the plug wire I bought was a strange lead coil one, and the inside is a kind of fibre. Should I replace it again?

    The strange thing is that if I go pretty fast the engine almost seems to carry me, and I can almost keep my momentum. But as soon as I go up a slight hill or hold in the clutch the engine dies instantly.

    is it possibly that I got a bad magneto or a bad CDI? I noticed that the wires are wired strange on the magneto, I included a pic.
     

    Attached Files:


  2. crassius

    crassius Well-Known Member

    that pic is the newer 2 wire mag

    CDI might be weak, as we've seen a lot of those this last few months, but if it goes fast enough to start sparking, then the motor should run OK

    if the CDI is weak, you'll need another one, but with the motor sometimes running, I'd also look for air leaks & gasket leaks (or I once saw a new muffler with some packing material clogging it)
     
  3. ChupaBaby

    ChupaBaby New Member


    Checked muffler and and it's clean. I've also checked my intake and exhaust gaskets and I've tried removing the muffler. It's strange, either I get a really good spark or no spark at all. And it seems to be completely random when I actually do get spark. Going to test the magneto and try to test the CDI with my ohm meter.
     
  4. crassius

    crassius Well-Known Member

    intermittent spark could be a wire that got crushed in shipping so that there is a break in the wire inside, while the plastic insulation is still in one piece outside - it'll make connection or not depending on how it is bent at any one time - this can be hard to find
     
    Timbone likes this.
  5. ChupaBaby

    ChupaBaby New Member


    Thanks Crassius, I've got some old wire laying around, perhaps I'll solder it on there and replace the old!!
     
  6. ChupaBaby

    ChupaBaby New Member

    Well, replacing those wires seems to have given me a good amount of spark! Upon trying to get it started again, it refused to start and i noticed fuel/oil basically sparaying out from the mating place between the cylinder and crankcase. I noticed that they arent mated properly, but my head bolts are torqued very tight. I read something about having to file part of the cylinder in order to get it to seat properly?

    Also, a pin and bearing fell from my drive sprocket when I had it open. Does the bearing go in, then the pin?
    IMG_1228.jpg IMG_1230.jpg IMG_1232.jpg IMG_1233.jpg
     
  7. Leroybrown420

    Leroybrown420 Member

  8. butre

    butre Well-Known Member

    bearing in first, then pin
     
  9. ChupaBaby

    ChupaBaby New Member

    Well guys, I ****ed up. I think one of my pistons got caught and when I attempted to start it, it wrecked havoc on my cylinder and piston. The cylinder is groove free and Ive still got one piston ring so theres still compression but I chipped a piece of my cylinder off. When looking down the intake with the piston at the bottom of the stroke, you can see into the cylinder. Air also seems to be coming out of my carb, as opposed to into it. Do I need a new cylinder? Can anyone recommend the cheapest place to find parts in BC? Thanks guys
     
  10. Curst

    Curst New Member

    My thoughts

    If you have a spark the next thing must be your crankcase/chamber pressure. I would say this diagnosis goes along with the engine seeming to have a little life in the way it "carried" you slightly. In your pictures your base gasket looked a little beaten up. Possibly even having some tears near the bolt holes? If that is the case, the pressure is being prevented from building up inside your engine and transferring enough fuel/air into your combustion chamber to produce significant power(but just enough to feel it burn). Also, check to make sure your intake gasket and carburetor/manifold seal are intact and air tight. Lastly, check to make sure both or your carb jets are fully screwed into their appropriate places. Good luck.

    Chupa: If your cylinder walls are groove free that is a good sign. However if you have any chips (or cracks) in the cylinder wall it's just a matter of time before the metal surrounding the chip also chips off and compounds your problem. As far as whether or not the engine itself will continue to work depends on the where exactly the metal broke off from (maybe post pics?) and if you have removed ALL of the broken chunks from the inside of your engine. The carb releasing air instead of taking it in sounds like a problem. I would recommend a new cylinder at least, probably with two new rings and maybe a piston head too just to be more safe.
     
    Last edited: Jul 10, 2015
  11. Leroybrown420

    Leroybrown420 Member

  12. ChupaBaby

    ChupaBaby New Member

    Thanks, I ordered a new cylider, piston and piston rings yesterday. If you're gonna do it might as well do it right!
     
  13. ChupaBaby

    ChupaBaby New Member

    Ordered a new cylinder, piston and piston rings the other day. Installed it all but now (of course) I'm having more issues. The new cylinder body doesnt have a angled inlet for the carb, so now my carb sits at 20 degrees and leakes fuel from the cylinder inlet.




    IMG_1274.jpg IMG_1275.jpg
     
  14. crassius

    crassius Well-Known Member

    did you consider using old intake on it?
     
  15. ChupaBaby

    ChupaBaby New Member

    I am using the old intake since the cylinder i ordered didn't come with one. Problem is, it's just a straight little tube, so it sits wrong on it.. Where can I find a angled tube?
     
  16. crassius

    crassius Well-Known Member

    never looked for one, but seems all parts suppliers should sell them
     
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