thanks from seattle

Discussion in 'Introduce Yourself' started by briane, Aug 15, 2013.

  1. briane

    briane New Member

    Ive been reading for about 6 months - thanks guys! helped me get 2 bikes together.

    First I built from scratch (lumpy/bob-ee)- getting brakes on it took some real thinking....Other I had built a while back (nicky), but then ended up swapping out, uhh - bout everything, engine, cdi, brakes, etc....Lots of fun - lumpy does about 30mph, nicky clocks at 26 - I think the big difference is the carbs...I'm more interested in the hill-climing and getting there than speed, seattle hills are a killer, and its more important to make it there in the first place.

    next task - use that CNS v3 carb - I know everone says toss it - but I already paid for it, so its going to be either that or the stock nt. just using up what I have around....

    Attached Files:

  2. KCvale

    KCvale Motorized Bicycle Vendor

    By your top pics you already have a newer (2010+) YD Skyhawk 2-stoke with CNS carb so I am a bit confused why you ordered another carb.

    What exactly are you symptoms as I find the CNS without an idle air mix screw and the Z intake to work great on a 66cc bike even when you add an X-pipe with no carb mods?
  3. briane

    briane New Member

    no, actually the CNS carb was lyiing from the REAL first bike -never got used - that I kept modding too much till I couldnt understand why it didnt run - then became the bike in the top with we new engine (turns out old still runs, was cdi) - no, thats an nt cheapo carb with a new air filter on it - thing is the lower bike (i call lumpy) has a speed carb and thing seems to rock out a good 5 hp more - so not knowing what else - and both bikes not being equal of course.....I thought the CNS on the top bike (nicky) might give it the power that lumpy has....They both run great just one gets a good 25% more power - and though exhausts are a bit different, etc... their ...kind of equal bikes...aside from the carb.

    thanks for the info - I think I need to use my CNS I have sitting around then for more oomph. thats a 2012 skyhawk.

    Still a bit confused about the hooking the port tubes together thing on the CNS- probably need to read up a bit more.

    I want to get em kinda - speedy, but dont want to get into ripping engines apart for now - I just want to ride em ;-)
  4. KCvale

    KCvale Motorized Bicycle Vendor

    There are 2 hoses coming from the top, one is a float bowl vent, the other is for the idle circuit, they don't need the tubes as all they do is keep water from getting in you can put a little foam or something over them to keep the dirt and water out but DO NOT CAP THEM OR CONNECT THEM TOGETHER IN A LOOP! They are needed fresh air vents not decoration ;-}

    The tube on the bottom has 2 functions, there is an overflow stem that goes up threw the float bowl but the drain set screw also uses it. Though you will never gas in the top 2 if you see gas in the bottom one you have a problem.

    I don't dink with the tubes, I just tuck the top 2 in by the top cables and either remove the bottom one or point the bottom one up so I can tell if it ever gets gas in it like this.


    I had lots of issues with the older CNS carbs, the rubber gasket for front inside wasen't wide enough and the darn idle air mix screw was no fun but no prob's with ones that ship now.
    briane likes this.
  5. briane

    briane New Member

    hey - thats the exact carb I got - so I just put it on - runs pretty good, but the idle is too fast...

    I see the screw in the side - maybe I need to figure out what that does or mess with that?

    The bike does go faster - just the idle races away. Its a way hotter ride.

    thanks for the support to just go for it - I think the CNS will work well if I mess with it a bit and get the idle down a bit.
  6. KCvale

    KCvale Motorized Bicycle Vendor

    There is only one adjust on the carb, an idle set screw, the farther you turn it in the higher it lifts the bottom end of the the throttle barrel.

    If your idle is changing it usually just your throttle cable slack not set right so when you turn your handlebars it effects the carb, you should have just a little slack in it and your throttle shoud snap back when released with the audible sound of that carb barrel slamming down on the idle adjust set screw.

    If that's ok it's a gas/air mix, too lean (extra air in the mix) the engine will rev up, you can see this by just shutting of the gas while it is running and let it idle, just as gas starts to run out it will rev.

    This could be from an air leak, a clogged gas tank filter slowing fuel flow to the point of not gas for demand at high end, or just a float bowl too low to keep up with demand.

    Of course another cause could be a bad case gasket that when warmed up shrinks and lets in the crankcase but you can usually spot that visually.

    Basic tips, hope one helps ;-}
  7. briane

    briane New Member

    hey thanks kc - after a ride or 2 the CNS idle seems to be working its way into goodness.

    I see a tiny bit of fuel in the bottom tube now - anything I should worry about?

    I think its running a bit lean. Can this be adjusted or do I have to put in a larger jet?
  8. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    There is an idle air mix screw on the YD carb.

    Remove the brass plug that is concealing it.
  9. LR Jerry

    LR Jerry Well-Known Member

    Baskets make our bikes useable as well as fun to ride.
  10. briane

    briane New Member

    haha - but mostly I need stuff! great for tools, tires, and fuel!
  11. KCvale

    KCvale Motorized Bicycle Vendor

    A tiny bit of fuel in the bottom of the bottom hose is normal overflow if you do hills, tip the bike sideways, etc, that's it purpose, to get the fuel out before it floods the engine.

    Whay makes you think you are running too lean, is your plug insulator bright white and not a shade of light milk chocolate?

    All I can advice you against everyone that says break the lock cap off the idle mix screw to adjust or change jets, etc, is at ~1500' altitude here in the desert the carps are perfect, changing the idle air mix is going to screw up your high end as they overlap in this example of the carb function.


    Lean is good so long as you don't get too hot and the right plug heat range decides that as much as the fuel mix looking at the plug.

    My point is simple and I mentioned it it, a good plug in the heat range for your use is pretty much all it takes, it's cheap and damn easy to try first.
  12. briane

    briane New Member

    yeah - its pretty white, but not bright - I think maybe I just play with a few variations on cooler plugs - maybe not even worth worrying about.

    Im at sea level =- and yes hills, every day, all day long.