80cc powerking motor 30km/h top speed

Discussion in 'Motorized Bicycle General Discussion' started by AnthonyX99, Nov 19, 2009.

  1. AnthonyX99

    AnthonyX99 New Member

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    Alright so I got 67cc/80cc motor from powerking at ebay engines great slow for the break I ran 16:1 for 4 tanks peak 2 stroke oil kinda crap but ran good alright the problem it was ok for it to be slow in a break in period it struggle to get to around 30km/h normal after about 200 miles it's the same I'm now running high quality am sol oil it hits 30km/h pretty fast lots of power except thats all it has to give when I open the throttle it goes then power is gone for 1 second then comes back and so forth I barley got it to 40 yet my new 49cc I got is silky smooth and fast very fast best engine I had yet and I mean no vibrations nothing. The 80cc engine is struggling for air or gas I checked for air leaks I change the gasket and used rtv blue seal left it for 24hr still the same I ported and polish the exhaust header and port still no power on the top end I'm going I checked the intake and see if the jet is clogged the spark plug is black same as the other one ngk brand and ngk boot brand new cdi box I just don't understand whats wrong I figure it might be the carb I'm gonna take it apart tomorrow and see whats wrong but some help would be appreciated it losses power on top end only going past 30 it struggles really struggles thanks again guys.
     
    #1 AnthonyX99, Nov 19, 2009
    Last edited: Nov 19, 2009
  2. bairdco

    bairdco a guy who makes cool bikes

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    sounds like you broke it in pretty rich.
    here's what i'd do:
    first, take the head off. the top of your piston's probably all black with carbon deposits. clean all that off with some carb cleaner and a soft toothbrush. you don't wanna use anything abrasive, 'cause it'll mess up your cylinder walls. clean the top of your head, too. get all that gunk outta there.

    second, clean your plug. or get a new one. use a file, and taper the tip of it a little bit. make sure it's gapped right (mine's at .28 -.30)

    third, move the clip on your needle up a notch.

    make sure your air filter's clean and reassemble all of it.

    that should work.

    after your first ride, while the motor's still hot, VERY GENTLY tighten your head bolts a little. just a little. this helps to seat them and keep them tight.

    after a few rides, check your plug again. if it's still black, go up another notch.

    during break in, your motor is just getting soaked with oil, and the carbon deposits build up. if you don't clean it up, it'll never run good.

    good luck.
     
  3. AnthonyX99

    AnthonyX99 New Member

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    Would I need to make a new gasket if I remove the head?? I ran the other one the exact same way and it's running really good.
     
    #3 AnthonyX99, Nov 19, 2009
    Last edited: Nov 19, 2009
  4. DonnnN

    DonnnN New Member

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    Try a new spark plug..

    My engine after break-in started acting weird the engine wouldnt idle well as if it was gonna die any moment..

    Couldn't ride at all.. I would twist the throttle and go but then the power is just weird for 1 sec i could accelerate then the next i would lose my power and then it'll come back..

    After i got a new plug everything went well..

    I guess during break all the 16:1 oil killed my spark plug
     
  5. DonnnN

    DonnnN New Member

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    Yes it would be best to fit a new gasket after removing the head the to make sure it seals well..
     
  6. bairdco

    bairdco a guy who makes cool bikes

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    when you take the head off, assuming there's no damage to the gasket, mark which way it's sitting on there, and put it back the same way. it should be fine. my kit came with two gaskets, and i've taken my head off 15 times, and i'm still using the same one. just be careful not to tweek it when you take it off.

    what donnN said about a new plug, if you've got a ngk already, just clean it up. those plugs last a long, long time.

    seriously, i think you can solve your problem without spending any money (except for buying some carb cleaner,) on new parts.

    everyone always assumes they need a new carb, a new plug, a new motor... but mostly, it's just basic maintenance.

    you're gonna get a lot of different advice on this. my advice, is do what's simple and free first. if you do everything i suggested and it still won't run right, then we'll figure out what to do next...

    these motors ain't to hard to figure out. they're using the same basic technology that's been around for a hundred years. don't over-think it.

    (that's my 2 cents, er... $149 + shipping's worth...)
     
  7. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Don't move your needle clip until after you go to a more reasonable fuel to oil ratio like 32:1 or 40:1. You may not have to move it at all.

    Clean the plug well and then run it. Have a look at the plug after you run it 20 or 30 minutes.

    Go from there.
     
  8. AnthonyX99

    AnthonyX99 New Member

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    yes i'm running 32 to 1 still no diffrence.
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Clean or replace the plug, and while it's out, look at it. What color is it? Once you know how the engine is running, you can diagnose the problem and fix it. Don't just start randomly chasing down phantom problems....get a baseline from which to start and then check/change one thing at a time.
     
  10. Riding Rich

    Riding Rich New Member

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    The 3 things that made the most difference for me.
    An expansion chamber / A Billet Intake / Replace the plug wire and boot on the CDI.

    Put these on and make sure the gaskets and everything match the ports.
    Don't grind at your Jug ports except to remove flashing.
    One cut too far and that thing will never run right.

    The other key is that e-clip setting.
    Try warming up the motor, ride it , then move the clip in one direction.
    If it feels like not enough fuel ( Carb slide is usually dry if running real lean )
    If the plug is really wet you are prolly running too rich.

    After you get some idea of which way to go move it 1 notch at a time and try each.
    If you move it one way and it runs woorse you went the wrong direction.

    Try all the possable e-clip positions until you find the one where it runs the best all around.

    Set the clip there ride it for a little wile and then check the plug color.
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    You should always check your plug BEFORE you make any changes.
    Looking at the slide is not going to tell you anything.

    Once again- Look at the plug, then
    Wet/oily/black=too rich.
    Brown, or dry and black=close to good.
    Gray, white=too lean.
     
  12. AnthonyX99

    AnthonyX99 New Member

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    I rebuilted the carb used a spare bottom of the carb I used a new jet needle tested it out ran pretty good but I'll find out how it really runs when i take it out for a long drive sparkplug is dry black sealed the intake with rtv blue also tighten the nuts as well.
     
  13. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Sounds like you got it sorted out pretty good then. A dry black plug is not the worst you can do...it may be just a little rich, but with these carbs, that may be good enough.
     
  14. Riding Rich

    Riding Rich New Member

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    Only my opinion.
    Yes the plug will tell you how lean / rich the mix is.

    But i like to find the best performance with the E-Clip then make sure it's not too lean.

    Anyway works for me.

    I actually run a bit rich but any leaner and i actually loose power.

    I need a more adjustable carb
     
  15. AnthonyX99

    AnthonyX99 New Member

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    Alright I took it out for a ride same thing no power on top end but I think I found out the problem my back motor mount is set to low and the carb is slightly lower and the intake is more down so I think there's not enough gas is getting to the engine for the next 20km/h might be that, after the engine cools down I'm going to realign the motor.
     

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