FOUR problems on my new chinese 2-stroke

Discussion in '2-Stroke Engines' started by djembefora, May 24, 2011.

  1. djembefora

    djembefora New Member

    hey, just mounted everything and hooked up all the cables and tubes and guts. i can get the thing to start but i have four discrete problems i have found... help with any of them would be much appreciated.


    1- there are two "throttle-looking" things with cables attached to them, protruding from my carberttor. all the diagrams i have seen only have a grip-twist shifter, but i also have something attached that looks like a down-tube style bike derailleur shifter. both have cables (similar to bike brake cables) which they control the tension of. both are attached into the carbertor where they are spring loaded. only the grip-twister seems to control the throttle; it also has the kill switch on it. what is the other one for?

    2- there is a LOT of resistance on the back wheel even when i have the clutch engaged. like, the only way to move the bike forward is drag the back tire or carry it.

    3- it dies any time i try to put it on a moderate uphill grade.

    4- the yellow kill switch (which is on the twist-grip from problem #1) does not do anything. i have tried a lot of different "wiring guides" to no avail. how do i attach a kill switch wire to the frame? from my engine i have a black, blue and white wire; from the cdi black and blue, from the twist-grip green and red/yellow.

    thanks!!! :D

  2. DuctTapedGoat

    DuctTapedGoat Active Member

    1. One is your choke - they did that on the CNS carbs.

    2. You need to adjust your clutch.

    4 Step Clutch Adjustment.

    1. Adjust the clutch's camshaft so that it is perfectly flat against the bucking bar.
    2. Put the clutch handle into the locked position.
    3. Adjust the flower nut CCW in very slow increments, checking to see when your bike rolls freely. Put the locking screw back in to lock the flower nut.
    4. Fire up the bike, lock the clutch and lift the back wheel off the ground. If the wheel moves, adjust the flower nut again.

    3. You can try adjusting your needle clip to lean it out. That or your choke is in. I personally would chalk it up to a CNSv2 carb.

    4. Best wiring is this.

    Don't attach anything to the frame!

    Blue to blue to red/yellow
    Black to black to green
    Cap off the white.
  3. djembefora

    djembefora New Member

    @ducttapedgoat: thanks! but what is a choke for and how do i use it?
  4. djembefora

    djembefora New Member

    oh, also, it wont idle. when i come to a stop, it dies.
  5. Al.Fisherman

    Al.Fisherman Active Member

    A choke is a restriction to the intake. It cuts air for a easier start in some bikes. If needed, once it warms up pull the lever down (off).
  6. hammer5312

    hammer5312 Member

    A choke is a design feature that makes the air/fuel mixture richer which causes the engine to increase in temperature, which once the engine is up to it normal operating temperature should run smoothly.
    Fuel injected cars & motorcycles do this the old days before electronic fuel injection, we would set the choke and fire up the motorcycle and as the engine warmed up the rev would increase as I was putting on the helmet and we'd have to stop and mess with the choke to keep it from over revving and then it would prolly die....
  7. DuctTapedGoat

    DuctTapedGoat Active Member

    The not idling could very well be your clutch. Fire it up, jump off the bike, hold the back wheel off the ground and hold in the clutch. If while you're holding in the clutch the back wheel moves, the clutch isn't disengaging completely.
  8. motorpsycho

    motorpsycho Active Member

    you need to adjust your idle screw to raise the idle up. screw it in to raise the idle, screw it out to lower the idle.
    the cns carbs are a pain for a newbie because they have an air-fuel adjustment screw as well as an idle screw(the idle screw should be the bigger screw on the left side of the carb.)

    as everyone else is saying, your clutch probably needs to be adjusted which is easy to do.
    with the clutch handle squeezed in, the rear wheel should roll freely (but there will be a little resistance because of the engine chain).

    if your kill switch doesn't work, you probably have it wired wrong....a simple fix.
    just follow the instructions above for the clutch adjustment and the wiring.
  9. Wolverine

    Wolverine New Member

    i just looked at the exploded views of this after having the same problem of my clutch not disengaging. i took off the side with the bucking bar and i swear i can not find the small little round ball that goes in before the bar. could this be a oversight or can it actually be missing? if so how do i get one or get this fixed?
  10. BoltsMissing

    BoltsMissing Active Member

    Don't even attempt to use the bike until that part is sorted.
    What I do is throw away the china toy bearing and replace it with a real ball bearing, at least.
    To go a step further, a bit pendantic, but I use 2 quality bearings and shorten the bucking bar.
    To shorten the bucking bar, keep grinding one end bit by bit at a time and fit back on to test till the cover sits flush.
    Don't shorten to much or it defeats the purpose. Zero tolerance works ok, it will wear in.
    File both ends till smooth then fine wet/dry "polish".

    To take it a step further, case harden both ends of the bucking bar using the heat-to-rosy-red-dip-in-fossil oil trick, and case harden the cam where it presses on the bucking bar to.
  11. Al.Fisherman

    Al.Fisherman Active Member

    I hate to answer here, might be better to start your own thread vs hijacking a previous post.

    Anything that the Chinese can be a oversight. You wouldn't believe the short comings of these Chinese HT's.

    First, is the bucking bar protruding about 1/4" from the shaft. If not I'd expect that the ball is missing. A pencil magnet is strong and small enough to insert in the shaft and pull the 5/16" ball out, should it be in there. If you want to make a new bucking bar, a 5/16" drill bit (the flute) makes a good one.
    Last edited: Aug 21, 2011
  12. BoltsMissing

    BoltsMissing Active Member

    Na, it's kool, all input and our own experiences makes a fine thread.
  13. Wolverine

    Wolverine New Member

    I'm just shocked that its missing. Where could have gone? It's not like it could have fallen out since it's fully encased. And to think it was put together without it amazes me. Where could i get one of these?
  14. srdavo

    srdavo Active Member

    find a ball bearing the same diameter as the bucking bar. The large ball bearings from a one pieced crank is close.

    I appreciate your searching & posting in a similar thread!!
    Last edited: Aug 21, 2011
  15. DuctTapedGoat

    DuctTapedGoat Active Member

    How do you know it's not in there. I mean, how sure are you?
  16. Wolverine

    Wolverine New Member

    Honestly I'm not 100% sure since I've only taken it apart once. But the bucking bar goes all the way in and is flush inside , if not going in 1/32 more and its still engaged. Almost like there is no ball inside or the bar is to short. I'm to the point I am going to just take it back to the guy who built it and see what it would cost to fix. I've rode it all of maybe 30 minutes so I'm hoping he'd understand and fix this.
  17. DuctTapedGoat

    DuctTapedGoat Active Member

    Okay, sounds like your ball bearing truly is gone. I did want to check first. Replace with an 8mm bearing, grease it and you'll be in business.
  18. BoltsMissing

    BoltsMissing Active Member

    The very first build, very first kit I bought in 2007 had this ball bearing problem.
    What happened was, after a few miles the clutch seemed odd.
    Fortunately we were near another builder's place, wheeled the bike there and we had to use compressed air to force the flattened, yes, flattened china toy bearing out. It took some doing with the compressed air nozzle, but it eventually came out.
    A magnet would not have had enough oommff to get it out.
    It had literally become flat, seized and blued.
    It was not proper bearing steal, I think they are round fishing line weights!

    So if you have already started you engine, chances are it is still in there, but flattened, or it's fallen out, or never was there in the first place.

    Every new kit I buy, I'm on auto-pilot in regards to replacing that particular bearing. Even if the vendor say's they "upgraded" the bearing, I don't give a stuff.
    At least I know where the bearing came from and it's not china-toy-steel.

    Just measured the stock I have, they are 8mm as mentioned.
    I buy them in 20's, enough for 10 kits, 2 bearings per clutch mechanisim method.
    One bearing still works, it's just me that I use 2 bearings with a shortened bucking bar.
    But don't do anything else till it's sorted or it may cause further damage.
  19. Wolverine

    Wolverine New Member

    Ok. I am going to sound like a complete idiot, but here it goes. I took the bike to the guy that built it and within 2 minutes he found the problem. Seems like I wasn't riding the bike correctly. He told me that when starting the motor I need to peddle, let go of the clutch, and KEEP PEDDLING, until the motor completely takes over. What I have been doing wrong is popping the clutch and just taking off letting the motor take the full torque of my weight and starting off by itself. The result was a bucking bar severely worn out with a HUGE divot on the end where the ball bearing would be. Resulting in a very short bucking bar. So, hard lesson learned, I rode today doing exactly as he told me and it runs like a dream. He also told me to save on wear and tear to do the same with full stops at a stop sign and starting off again. Thanks everyone for your help and hopefully anyone that reads this in the future will not make the same mistake I did.
  20. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    No need to find a 8mm ball bearing as a 5/16" ball bearing is close enough and works fine.

    Ace hardware has them for cheap!