Motor bogging at start up low speed

Discussion in 'Motorized Bicycle General Discussion' started by AaronF, Sep 6, 2009.

  1. AaronF

    AaronF New Member

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    When i turn the engine on the motor bogs pretty bad making terrible vibrations through the whole bike.Not sure what could be causing the bogging,i just cleaned the carburetor filter and put on a new fuel line/stock air filter.I've adjusted the idler screw numerous times an it still bogs.Any suggestions to this?Thanks
     
  2. GearNut

    GearNut Active Member

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    What kind of engine setup?
     
  3. AaronF

    AaronF New Member

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    Totally forgot to say what kit i have,sorry bout that.I have the 2 stroke 80cc=66cc engine with all stock gaskets filters etc.
     
  4. GearNut

    GearNut Active Member

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    Bogging could be an intake air leak, air leaks at the crankshaft seals, plugged up exhaust, choke left engaged, rich fuel mixture, bad gas. There are alot of variables. What color is the sparkplug? Black, white, or tan. The color can tell you alot concerning what is happening inside the combustion chamber.
     
  5. AaronF

    AaronF New Member

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    I will check the spark plug here soon and let you know the color of it.I also forgot to mention,i just installed this new kit two days ago with 40 miles on it already.Note that when i mixed the gas/oil i don't have a gas measuring cup,so there for I'm not sure if the correct amount was used for the first tank,the ratio is supposed to be 16:1 The carburetor was clean as clean gets,i just cleaned the float bowl as well.It seems as when I'm not using the throttle,the idling is pushing me down the road at 10MPH witch is weird..
     
  6. DonnnN

    DonnnN New Member

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    You're Not Twisting The Throttle And It Goes 10MPH? Wow How Far Have You Unscrewed This ? (See Pic)


    [​IMG]




    The More You Unscrew That The Engine Will Rev MORE.. And Adjusting The Idle Screw Won't Work..
    So Try That First.. ; ) Hope I Helped
     
    #6 DonnnN, Sep 7, 2009
    Last edited: Sep 7, 2009
  7. AaronF

    AaronF New Member

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    The only thing i have tried is messing with the idler screw,i have not tried the throttle twist yet and personally i didn't know it did anything!I will give that a try in the morning and post with the results.By twisting it up/down what exactly does that do?Give more speed/performance?Thanks!

    Strangely yes it does push me along at 10MPH without throttling,i was kind of amazed at that but i do know its not supposed to do that lol.
     
  8. AaronF

    AaronF New Member

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    I would also like to know some modifications that can be done on the cheap for better performance.Such as a cheap muffler,carburetor air filter etc. any suggestions websites would be great,Thanks!
     
  9. BarelyAWake

    BarelyAWake New Member

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    Well, firstly the idle set screw adjusts only the idle, it does this by limiting how far down the slide can go, thereby allowing more or less fuel to the engine - but only at idle. So while you do need set this (engine off, screw it in all the way gently & by hand - then back it out 3 & 1/2 turns for approx idle speed, then fine tune w/engine running) it wont do anything for a fuel/air adjustment. That is the small C-clip on the needle inside the carb - usually the second slot down is the average setting - but every motor is a little different, always check plug coloration when messing about with your fuel/air ratio.


    Just wanted to mention that these china 2 strokes are renowned for running like crap until broken in. Mine was 4stroking (misfiring every other stroke) so bad for the first hundred miles or so despite all attempts at adjusting fuel/air that I considered junking the dang thing.

    Now that I've got about three hundred miles on it - it's a night and day difference. I'm not suggesting that you shouldn't attempt to tune it in, I just wanted to reassure you that it isn't just a matter of mix - ya gotta ride the thing till ya bleed!

    Spookytooth, Bikeberry, Sick Bike - most of this forum's sponsors are quite good if yer lookin for upgrades btw, and the performance subforum here is ossum :D I would actually suggest replacing the carb with the following as the 66ers carbs are garbage;

    CNS Aftermarket Carburetor for Motorized Bicycles w/ Adjustable Air-Fuel Screw (air filter, cables, grip & kill inc) Price: $50.00
    [​IMG]
    Spooky Tooth Cycles - Motorized Bicycles: Gas Powered and Electric Bikes - CNS Carburetor for Motorized Bicycles

    Cheap muffler? I suppose you want an inexpensive tuned pipe... Though I don't much like the Machiavellian method or the various plumbing fixtures, this setup is one of the least expensive (also available in chrome);
    Black Expansion Chamber Exhaust Pipe [SBP-ES002] $64.95 Sick Bike Parts

    however - for the money, this 'un is soooo sexy;
    New SCSW Tuned Pipes for sale! $120 Pipelyne Manufacturing. (408) 279-2307 http://motorbicycling.com/f23/new-scsw-tuned-pipes-sale-189.html


    Hope this was some help - just remember to get some miles on yer bike, not that it's much of a chore heh
     

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    #9 BarelyAWake, Sep 7, 2009
    Last edited: Sep 7, 2009
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    A couple of notes-

    16:1 is TOO MUCH OIL! Go to 24:1.

    10 mph at idle? I think that's about right..below that you should have the clutch in. If it revs up with the clutch in, turn down the idle, or check for an air leak at the manifold to cylinder junction.

    Get a measuring cup, or use the side of the bottle of oil where it is marked for oz. increments....never just "guess" at the engines life blood. (oil)
     
  11. AaronF

    AaronF New Member

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    Very informative information i did not know alot of it!My first kit i got was two weeks ago i got it up and running it was badass it would go 40mph during the break in witch is my kind of thing,though i didn't do it to much.Then it went to crap the muffler blew to pieces,engine cylinder intake mounting studs were stripped out from the muffler flying off my bike:-|| Now this new kit is great besides the few small problems I'm having making the correct adjustments.My next tank of mix I'll be sure to mix 24:1 for the break in period and go from there.

    I sure do like the looks of that carburetor man it will go good with my blue diamondback! I'll be checking the spark plug end color,adjust the idler screw and throttle screw then I'll post with the results!Thank you
     
  12. AaronF

    AaronF New Member

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    I just got back from a 4-5 mile ride around the neighborhood it went fine.I adjusted the idle an the throttle screws to where there is no bogging.When i adjusted the throttle cable twist upwards i noticed the engine would rev more making it louder,by doing that i noticed a 2-3 mph in gain but without throttling it is going 12 mph..My bike has the same setup as the first kit i had installed an this kit is the same kit but a new one.I'm not getting the torque like my first kit would produce,it will only reach 24 mph right now i know the engine is still breaking in but besides that,i like to throttle it almost all the way a few times during my ride xct2

    When i installed the new kit i didn't use the carburetor that came with it,i used the first one i had witch was used..Could that be doing something?
     
  13. AaronF

    AaronF New Member

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    So i checked the spark plug an the color is black and the tip of it is pure black.I seen on here the color should be tan like to be "clean running" what is causing this?what should i do? Thanks
     
  14. GearNut

    GearNut Active Member

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    If you are still breaking in the engine, the richer ratio of 2 stroke oil will darken the sparkplug more. A new engine is better on the black side when breaking in. It needs the extra oil.
    I suppose you could raise the clip (away from the pointy end) on the jet needle one notch to lean out the fuel mixture. Just be careful. Too lean will do damage. Check the sparkplug color a couple of times during the next ride to be sure it is not too lean.
     
  15. stv1jzgte

    stv1jzgte New Member

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    You did 40 mph during the breakin? Awesome! What is actually wrong with the 2 week old 1?
     
  16. AaronF

    AaronF New Member

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    Yes i did 40MPH with the first build i had going it was super fun i tell ya man!

    The engine cylinder exhaust mountings were stripped out,i tapped them to 1/4 20 and i guess i didn't tap it straight in there so the engine cylinder needs replaced.I was told it would be hard to find the correct cylinder for it and would cost me more than another new kit to have it rebuilt.I thought i could just get a replacement 66cc cylinder off of ebay for $20 and be done with it? I would like to get that one going for another build because its practically new still..Any thoughts?.wee.
     
  17. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Just buy a new cylinder FROM YOUR ORIGINAL SELLER. You should get the right one that way.
     
  18. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    BTW- It sounds like you are using the cable adjuster on the top of the caerb to pull your throttle cable up. The correct way is to adjust it so there is "just free" amount of play in it. In other words when you pull up on it, you should just perceptably feel it move.
    The scrwew on the side of the carb is for adjusting idle speed, and speed alone. There is no mixture screw.

    I also second the motion for you to move your "C" clip down one notch on the needle, and check the plug after a few miles.
     
  19. AaronF

    AaronF New Member

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    Right now I've gotten everything up an running smoothly no bogging involved..I did change out the spark plug with a auto lite not sure of the model # but after 5 miles with that new spark plug the bike suddenly had a boost in torque cvlt1 My only problem now is getting flat tires,I've had three flat tires in three days with new tires even..
     
  20. AaronF

    AaronF New Member

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    Re: Motor still bogging pretty bad

    Alright so I'm needing your help again the motor is bogging pretty bad at start up and when i slow down..I've adjusted the idler screw as mentioned,did a 24:1 mix on the next tank and this thing is still bogging at start up and when i slow down.I've also used gasket sealer for the intake to the carburetor in case there were any leaks..Am i supposed to gap the new spark plug on these motors,if so how? Thanks again
     

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