Please help

Discussion in 'Bicycle Repair' started by Jayson, Aug 30, 2016.

  1. Jayson

    Jayson New Member

    Okay so I bought an 80cc motor kit not too long ago build went fine motor ran great right out the gate. I ran several Rich tanks through it to make sure I broke the motor in properly. When I was sure the motor was broken in I took it on a 4-mile run, everything was still fine the next day I decided to remove the baffle and see if I gained any power. After about 5 minutes of riding without a baffle the motor cut off. After removing the head and checking all the gaskets replacing the spark plug and replace the carburetor because the float leaked and filled with gas I still get nothing more than one pop when I release the clutch. I know I have gas flow, I know I'm getting air, and I know I'm getting spark. So. Now what? I'm at a loss at this point I can't figure it out please help
     
    Last edited: Aug 30, 2016

  2. Are you 100% sure your getting spark?
     
  3. jaguar

    jaguar Well-Known Member

    popping is usually a bad head/cylinder junction.
    these heads come warped from the factory. Plane it flat with sandpaper on glass and make your own head gasket out of hi-temp gasket material (I think O'Reilly has it)
    Also the metal to metal contact at the stator coil where the screw heads contact it is often fault due to shellac there. clean it off.
     
  4. Jayson

    Jayson New Member

    If my head was warped wouldnt there be gas coming out the side of the head were the leak is? As for the coil do you mean the mounting screw's or the wire that connects to the spark plug? Because the wire that connects to the spark plug is clean. I know I'm getting spark out of the head and I believe I'm getting spark in the head because I do get that one pop once I release the clutch
     
  5. Jayson

    Jayson New Member

    Update: so today I took out the ngk spark plug and put in the original that came with it now it still does not run but I am getting several pops within a few seconds if each other
     
  6. Squirt a tablesoon of gas/oil mix into spark plug hole.
    Install spark plug.
    Re-attempt to start it, and see what happens.
    If it runs for a moment, then I believe your issue is fuel related.
     
  7. Jayson

    Jayson New Member

    Have tried and just installed a brand new carburetor still nothing
     
  8. jaguar

    jaguar Well-Known Member

    the screws holding the stator coil onto the cases
     
  9. jatgm1

    jatgm1 Member

    you could attach the cdi wire to another known good spark plug and then spin the engine at the speed its intended to go (with a drill or something) to see if their is a spark coming across the plug, if their is then the coil is producing electricity and the cdi (or cdi and ignition coil if their separate) are working properly, so its getting a spark. you could then take off the air filter, and spray starter fluid into the carb, and if it starts for a second then stops or starts firing at all then you know that the carb isnt giving gas properly. in which case it could be something as simple as the petcock valve being off or the fuel line (or petcock valve or gas tank opening or fuel jet) being clogged or partially clogged. the petcock valve that came with mine was problematic. i would start the bike and ride it, then after a bit it would start running lean, then stall out. or the carb is either clogged or not adjusted properly, you say you installed a new carb, which kind of carb? is it a dellorto, cns, or nt? from what i understand, the NT do work right out of the box most of the time, whereas the cns requires tinkering to get it functioning many times, and the dellorto needs the proper jet size (this i know from experience, the stock jet i had worked for me but was too lean, i had to order more jets.) if you dont want to order a fuel petcock, you can probably get a hose barb adapter from home depot or something that fits the fuel tank. just bring the petcock valve in and say you need a hose barb adapter with that size threads on the other side, then use an inline fuel valve if the carb leaks. i did that until i got a petcock valve. (you might want to drill the hose barb adapter to make it wider to get better fuel flow, i did, just clean the metal shavings well afterward so they dont mess up the carb or cylinder.) there could also be loss of compression. im yet to have that issue, but i believe their is a tool for measuring the cylinder's compression, unfortunately im not sure what it is, as ive never needed it, but maybe someone else knows what it is and how it works.
     
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