Hey

Discussion in 'Introduce Yourself' started by Brent436, Feb 14, 2010.

  1. Brent436

    Brent436 New Member

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    Hey everyone,

    I recently put a Grubee 48cc motor on my bike. I've had some problems so I came looking for some help. I graduated top of my automotive class in tech school and have a lot of experience with engines. I'm kind of embarrassed that I have to come asking for help but I just can't seem to get the motor running.

    The first time I tried to start it the motor took a while to start up. When it finally started it ran real rough and i would have to keep hitting the throttle to keep it running. While it was running it seemed to backfire a lot. After that I stopped the engine and couldnt get it started again. I Have spark and its getting gas. I have sealed the carb and am waiting for the RTV to cure to try it again. Any suggestions to what else could be the problem would be appreciated. Once I'm considered an active member I will post this in the troubleshooting section. Thanks for all your help.

    -Brent
     
  2. professor

    professor New Member

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    Hi Brent, welcome to motorbicycling! I think you located the problem. Definitely lean.
     
  3. 2door

    2door Moderator
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    Welcome Brent,
    You've come to the right place for help and no need to feel bad about asking for it. We all had to start where you are. The Professor is right; sounds like a lean condition most likely from an air leak in the intake/carb area. Get back to us if this doesn't take care of your problem. We're here to help.
    Tom
     
  4. Brent436

    Brent436 New Member

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    Back again guys,

    Thanks for your help but it still doesnt run. The carb is all sealed up now. I tried starting it this morning but it still wouldnt start. i opened the carb up and the black c-clip was at the third notch from the top. I've read in other threads that the best setting is second from the top so i moved it there. Tried to start it after that and it fired once. After a little while of still trying to start it, it fired once more. Since then I havnt been able to get it to fire. I'm in Massachusetts right now so its cold but its above freezing so i figure it should be able to run. Does anyone have a recommendation to where the idle screw should be set at? I've tried 4 1/2 turns out like the manual recommends and I've tried 3 turns out like other people on other threads have recommended. I'm gonna try some starting fluid now. Any help is greatly appreciated!
    Thanks for the help,
    Brent
     
    #4 Brent436, Feb 15, 2010
    Last edited: Feb 15, 2010
  5. Brent436

    Brent436 New Member

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    Another quick question: if i take the throttle cale part of the carb out (with the plunger thing out) and turn the motor over, is fuel supposed to come out of the hole looking straight down into the carb? From what i understand thats where the fuel comes out of and none is coming out on my motor.
    Thanks again,
    Brent
     
  6. Brent436

    Brent436 New Member

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    Hello again,

    Brand new 48cc Grubbee Skyhawk still isnt running. I replaced the stock plug with a champion E3 Diamond fire plug. I closed the gap to .020 as suggested by other troubleshooting threads. It fires a lot more and is very close to starting. At this point I'm lost as to what i should do to get it running. The best guess that i have is that its a carb problem. If you have any suggestion as to what i should do please say something. Thanks!

    Brent
     
  7. Nougat

    Nougat New Member

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    Yes, that's where the fuel comes out, but if you're looking down the open top, you probably won't see any fuel coming out anyway, because of the air getting pulled down the top of the carb. Best way to see if you have fuel is to turn it over a few times and pull the plug. If it's not starting, the plug will be wet.

    You can check to see that fuel is getting into the bowl by opening the drain screw on the bowl. If fuel comes out - there's fuel in there!

    If you have fuel in the bowl, but a dry plug, you probably need to adjust the float height, so that the float rides a little higher in the bowl before it closes the needle valve. There's a little piece of metal with a couple of arms on it; bend those arms up just a bit, and the float will rise higher before closing the fuel inlet. While you have it out, make sure the float isn't cracked. If there's fuel in it, you need another one.

    From the sound of it, with sputtering like that but not running, I'm putting my money on float height.

    Oh, one last thing - make sure you're running between 24:1 and 32:1 for your fuel/oil mix. 16:1 in the instructions is too oily. If your plug is wet, this might be your problem.
     
  8. Brent436

    Brent436 New Member

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    Hey,

    The plug is wet after trying to start it a few times so it is getting gas. I suppose either later tonight or tomorrow I'll check the float height and adjust it like you said and try starting it again. Thanks for the help.
    -Brent

    Edit: Right now im running 18:1 like the instructions say for break in. Ill add more gas to the tank to lower the percentage of oil. I will probably try this before opening the carb up to check the float. Thanks again.

    -Brent
     
    #8 Brent436, Feb 15, 2010
    Last edited: Feb 15, 2010
  9. Nougat

    Nougat New Member

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    Better to drain the fuel out of the tank and the carb and remix it in the can, then fill it up again. Make sure to do the math so you know what mix you're running!
     
  10. Brent436

    Brent436 New Member

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    Thats what i meant haha. Thanks for making sure i didnt do anything stupid though!

    -Brent
     
  11. corgi1

    corgi1 New Member

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    Do we take out the plug ,hook up the wire,lay the plug on the head and spin the motor to see if the mag is throwing a good spark:confused:
     
  12. Brent436

    Brent436 New Member

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    Yeah thats how you check for good spark. You just have to make sure the electrode is grounded to the engine block. I recommend buying a better plug than the stock plug that comes with it. I replaced mine and its got a lot better spark than the stock one.
    Hope this helps,
    -Brent
     
  13. Nougat

    Nougat New Member

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    There was someone else recently who was getting spark outside the motor, but the bike still wouldn't run. Replacing the CDI fixed this, though I'm not clear on whether he'd tried replacing just the plug wire or not. Apparently, there wasn't enough juice to spark good under compression with fuel, but enough to spark where he could see it.
     
  14. Ghost0

    Ghost0 New Member

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    I was helping another rider troubleshoot a similar no start problem and it was the ignition. Plug out of the head had great spark but would not fire in the head. He replace the CDI and Mag and then it ran. Don't know for sure which one was the actual problem.
     

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