Having small issues with first motor, trouble starting.

Discussion in '2-Stroke Engines' started by fallstherain, May 9, 2010.

  1. fallstherain

    fallstherain New Member

    So, I just made my first MB. I used a 66cc grubbe skyhawk 2-stroke on a greenline beach cruiser. I installed everything a couple days ago and rode it around a little but I had some huge tensioner problems. All the bolts already stripped on the kit tensioner just from adjusting a few times. I'm currently trying out a ghost ring tensioner and it works great as long you have it shoved in the chain far enough.

    When I first built the engine it would start up fine every time. First try it would usually start up and I could ride it right away. Yesterday the engine started doing this thing where you had to try starting the engine a few times before it would actually stay on. I would ride it with the clutch in, let it out, and the engine would start and then slowly shut off. If I pulled the clutch in once it started it would turn off instantly. If I give it gas, it might rev a little, but not enough to keep it going. After trying to start it maybe six times like this it finally kicks in and stays on. Let it warm up a little and it still runs great. This process has happened a couple times now and seems to happen any time the engine has been off for about and hour or more. I'm pretty sure this isn't what should be happening and I'm wondering if anyone has an idea of what it could be.

    I also replaced the kill switch yesterday morning with a home-made toggle switch (on-off). The toggle switch is an inline blue wire kill switch and it still works great to kill the engine. I used speaker wire from an old stereo I had to connect the blue wires to it. Could this be what's causing the problem? Thanks for all your help.
    Last edited: May 9, 2010

  2. motorpsycho

    motorpsycho Active Member

    check for good, constant flow of fuel out of the gas tank petcock. sometimes, the tanks have junk in them from the factory, and the screen on the inside of the tank (on the end of the pet-cock) will get plugged up.
    restricted fuel flow can cause the problem you describe, because if the needle & seat in the carb are open and "asking" for fuel...restricted fuel flow will take longer for the float bowl to fill up. by the time you try to start it 5-6 times, the fuel would be able to trickle into the float bowl and fill it up.
    also check your in-line fuel filter (you do have one right?)

    ummm, speaker wire for your kill switch?
    I would get rid of that because speaker wire is not made to carry much voltage.
    the speaker wire could be part of the problem sue to the wires resistance, but i'm not positive. are you useing the kit supplied crimp on connectors on your wires? if so, do yourself a favor and cut them off. Solder all wire connections and cover them with heat shrink or black tape. The kit supplied connectors have a lot of resistance, they break easy, and will eventually vibrate apart. if by chance, a bare wire is touching the frame , the engine or anything metal, you will have ignition interruptions.....and this too could be causing the problem you are describing.
  3. Al.Fisherman

    Al.Fisherman Active Member

    I'll go along with the fuel situation ideas above. As far as the wire, speaker wire is overkill. The wires coming off of the kill switch, CDI and the coil will be anywhere from 20 to 24 gage (6-7v @ less then 1 amp). Speaker wire is 16 gage and a auto marker light (tail, stop and parking) is about a 16-18 gage (12v @ 10amps). I replaced all wires that the magneto had with 18 gage. Wired the rest of the bike with 18 gage. I removed the wires on the magneto and ran single (unspliced wires to the CDI. The kill switch wires were long enough to reach the CDI.
    Last edited: May 9, 2010
  4. fallstherain

    fallstherain New Member

    Hey, thanks for the replies. I looked into the speaker wire issue and used a larger wire. Al.Fisherman, were you saying that speaker wire is bigger than what is needed? The stuff I used was much smaller than the wire that came attached to the engine. With the new wires on it still had the same issue. I'm not positive, but I'm pretty sure that it is getting the needed amount of fuel. I will look into that tomorrow maybe. Another possibility I am considering is the spark plug. I still have the kit spark plug on the bike and I know those aren't very good. Would a spark plug do this to the engine? I would have tried that theory today too, but once I finally got it started I ran over a bent nail and it miraculously went in one side of my tire and out the other, resulting in a flat. Let me know what you think about the spark plug. Thanks a lot!

    Here are some pics from before I changed the wires.

    <a href="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3627.jpg" target="_blank"><img src="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3627.jpg" border="0" alt="Photobucket" width=300></a>

    <a href="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3628.jpg" target="_blank"><img src="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3628.jpg" border="0" alt="Photobucket" width=300></a>

    <a href="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3629.jpg" target="_blank"><img src="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3629.jpg" border="0" alt="Photobucket" width=300></a>

    <a href="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3630.jpg" target="_blank"><img src="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3630.jpg" border="0" alt="Photobucket" width=300></a>

    <a href="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3631.jpg" target="_blank"><img src="http://i112.photobucket.com/albums/n166/fallstherain/DSCF3631.jpg" border="0" alt="Photobucket" width=300></a>
  5. Al.Fisherman

    Al.Fisherman Active Member

    Last edited: May 10, 2010
  6. Big Red

    Big Red Active Member


    This might make me look silly, but I didn't see where anyone else asked. Did you put the right mix in yer gas? If the piston is seizing on the cylinder it would put a real drag on your engine.
    Hey, Just asking.
    BIG RED.