Carby CNS bye bye

Discussion in '2-Stroke Engines' started by wan37, Feb 22, 2012.

  1. wan37

    wan37 Member

    I have a nt carb setting here to swap,but it won't go on the intake all the way.I thought about rubber washers.I think that wouldn't work either,because the intake gets hot and It might melt the rubber.any Idea's.I can buy a new carb but don't know which one too get? The reason I'm getting rid of the cns, because it slides around too much on intake.
    Last edited: Feb 22, 2012

  2. geebt48cc

    geebt48cc Member

    Hey Wan,

    I've had a CNS on shelf for yrs........(WON'T WORK) Go with "SPEED" carb.......I've got one with 1000 miles on it, and it works very well for $$$$.
  3. VROOM

    VROOM Member

    I put the rubberized handle from a pair of pliers inside the carb opening and reamed it open a tiny bit more. Worked like a charm.
  4. machiasmort

    machiasmort Active Member

    I've got a two stroke carb from a B&S lawnmower engine. Of any interest? to anybody? It's rebuilt and pretty clean. I just don't have the time, they sell for $50 + shipping on E-bay. I'd pass it along for 1/2 that to one of my brothers here.

    Just an idea for ya's! I got to **** old too quick! LOL!
  5. motorpsycho

    motorpsycho Active Member

    briggs & stratton made a 2 stroke? on a lawnmower?? I never knew that.
  6. wan37

    wan37 Member

    I just don't understand.It still runs like **** with the nt carb too hard starting at times and no mid throttle at times,back fires and cuts out.It will idle for a couple minutes and then idle down and then die hard to start it again then.Please help me with this I'm tired of thinking what it could be.
    Last edited: Feb 23, 2012
  7. motorpsycho

    motorpsycho Active Member

    not sure if this has been covered with you yet or not...
    but do you have anything hooked to the white wire from the engine?
    is the white wire cut off and capped so it can't contact anything?
    the problem that you are describing is exactly what will happen if something is hooked to the white wire or if the white wire is grounding out against something.
    You may already know this, but I just had to suggest it.
  8. wan37

    wan37 Member

    I had a light hook to the white for a long time but cut it off about a month ago and caped the end.Yes I thought that is why I cut it and caped it.So
    I thought it might have ruined my coil or cdi.Because it hasn't got any better.I really am Out of Idea's.
  9. motorpsycho

    motorpsycho Active Member

    I would place my bet that your coil is weak. weak spark will also cause the same issues that you are describing.(from what i've personally seen anyway.) I just went through this same thing on my friends bike, and the coil was the culprit. he too had a light hooked to the white wire for awhile and then out of the blue, the engine wouldn't run very well, it would pop out the exhaust, lose power and die when you would try to idle it.
    having a light hooked to the white wire will cause your coil to be overworked.
    I have no idea how to test a coil tho, so you may want to find out how to do that, just to rule it out.
  10. wan37

    wan37 Member

    thanks again motor.
  11. wan37

    wan37 Member

    Can anybody tell me how to test a coil,and how too remove the nut on the magnet to check timing woodruff key .Thanks
  12. VROOM

    VROOM Member

    To test the coil you need to pull the spark plug and kick the engine over with the plug laying across the engine head. There should be a bright blue spark and an audible "popping" sound from the arcing current.
    Im not sure how to remove the coil.
  13. HeadSmess

    HeadSmess Well-Known Member

    jam it with a screwdriver? get a 14mm spanner on the nut? turn it anti clockwise?

    pull rotor off?

    may need to pull magneto coil first?

    if the rotor laminations have slipped and jammed the key...good luck?

    it happens, you know... :(

    if you really want to test the coil...the magneto coil that is, hold blue onto either pole of a car battery. then touch the main body of it (the steel laminations, or black...) onto the other for a second. quickly pull off.

    if nothing happens, its stuffed :)

    do the same with the white wire instead of blue.... :D
  14. wan37

    wan37 Member

    thanks headsmess.I got the nut off and the magnet key way was in the right spot.So it's got to be the coil (magneto ) or cdi!.I ordered them will be here Wednesday.I'll let you guys know what the culprit was.
    Last edited: Feb 26, 2012
  15. wan37

    wan37 Member

    Well the culprit was the magneto but order a replaced cdi too.......Thats a bunch guys
  16. V 35

    V 35 Member

    I'm thinking = bad coil / plug lead / cap Next time it conks out, shut off gas, and open bowl drain, measure how much fuel comes out. If the bowl is dry,
    needle and seat / clogged line/ clog at tank ?

    The fact that it ' sometimes ' does it, makes me feel like their are times when it runs correctly ? A bad carb will * never run right, a faulty CDI box
    may often fire until heated, or jarred.
  17. wan37

    wan37 Member

    Okay it's getting gas and no restriction on fuel because tried two different carbs.
    a NT carb which is new,and a CNS which ran great all last summer.Replaced coil and cdi yesterday help a little but still think it could be out of time,because it's still back fires alot out the exhaust with both carbs.Is it possible to be out of time and how do you fix it?
    Last edited: Mar 1, 2012
  18. wan37

    wan37 Member

  19. HeadSmess

    HeadSmess Well-Known Member

    turning the magnet the way the engine turns advances the spark, and backing it off retards...

    problem is you cant really see what is happening as you tighten the nut.

    ive had some magnets that dont have any "slop", others with over 30degrees of play! those last ones can make it either not run at all...too advanced, or scream... or just run. depends on where it is exactly.

    what the tutorial doesnt say is that its handy to lock the crankshaft as well as the magnet while tightening the nut again!

    take the clutch cover off. pull out the screw and replace it with a...m6? cant remember... socket head screw so you can "adjust" the crank position relative to the magnet(held with a screwdriver etc) while tightening nut.

    you can file the key and or magnet slot OR the leading/trailing edges of the magnet or stator (coil), all to affect ignition timing.

  20. HeadSmess

    HeadSmess Well-Known Member

    oh wow i like those starfire coils! like a brushcutter! combined coil!

    this was the first mod i thought of when i got a ht but didnt pursue!

    (sticking magnets into a hi speed rotor is...tricky)