Upgraded Carb

Discussion in '2-Stroke Engines' started by Clotho, Jul 10, 2008.

  1. Clotho

    Clotho Member

    When I purchased my Powerking kit I paid the extra for the upgraded carb. It is a bit larger and has a cable operated choke. This carb has an idle adjustment as well as another adjustment beside it. Does anyone have any documentation on this carb? I would like to tune it a bit but I don't know anything about it. The lean/rich setting on the pin is pretty much the same as the old style. I just would like to know what this other adjustment is for.

  2. BoltsMissing

    BoltsMissing Active Member

    Can you post some pictures so we can clearly see how it it looks showing every angle of detail ?
  3. BSA

    BSA Guest

    I was always under the impression that the upgrade carb had a mixture screw aswell as idle screw.

  4. Clotho

    Clotho Member

    Here are two photos of the carb. I pushed the fuel filter out of the way for better viewing. The screw on the right is the idle adjustment. the screw on the left must be the mixture adjustment. What is the best procedure for adjusting the mixture? I am familiar with the rich/lean pin adjustment on the barrel as well. It is the same on this carb as on the standard one. This carb just has 5 slots on the pin instead of 4.

    Attached Files:

  5. BoltsMissing

    BoltsMissing Active Member

    Thanks for the pics, appreciated.

    Beyond my comprehension though at this stage.
    Mixture screw, Idle screw, some have choke adjust, but by the sounds of it, seems it has mixture screw AND pin adjust...,

    I think this needs to be disected...,
  6. I have had one of these carbs for over a year. Put 1600 miles on it, but removed recently because it needs a rebuild now. It's commonly referred to as a "CNS" and increases low-end torque significantly (nice with small sprockets!).

    Adjusting the mixture via air screw takes a bit of trial-and-error. I screwed mine all the way in and then backed it out 1.5 turns, worked best for me. I did not adjust the pin setting.
  7. I have always adjusted them by starting the engine, increaseing the idle, adjusting the mixture screw for highest engine speed, and then turning 1/2 turn in, so not to have lean condition.
  8. Skyliner70cc

    Skyliner70cc Active Member

    Where does one BUY this carb and is rejetting needed? I had a Dellorto clone that worked great but the high speed jet was too rich for my altitude in Colorado.
  9. Rejetting may be necessary at high altitudes. But know this: if you live in a dusty area or ride off-road alot, the CNS carb will need a rebuild quicker than the stock one. It has 3 little ports that look like they require a vacuum hose on, but are supposed to be left open. This allows more tiny junk into the carb's sensitive parts.

    I've tried capping mine but the carb didn't work right. I've also tried capping the troublesome fuel overflow hose and the carb didn't work right either. Closing the fuel tank valve is also more important with this one. The carb is vented and fuels moves quickly through it!
  10. Hmmm interesting....I wonder if the little holes in the carb could have a hose attached to it and somehow run it to some nipples behind the air filter or maybe have a separate air filter for them (Like the PCV filters in cars)?...Might keep things cleaner for the carb that way...

  11. arielatom300heps

    arielatom300heps New Member

    Do u think it is worth the money for the increase in performance that u get from this carby?

  12. wayde

    wayde Guest

    i have th is carb too and know nothing about it
  13. Clotho

    Clotho Member

    Hard to say. It is more adjustable than the standard one. It takes up more space however. It doesn't seem to improve performance any but it may work better with engines that have been modified.

    I solved the problem btw. I adjusted the needle to the leanest setting and then adjusted the mixture setting till it ran best. (all the way in) It seems to be at the leanest setting possible but my plug is telling me that the engine is still running rich. It does run much better however.

    Thanks for the help everyone. :grin:
  14. arielatom300heps

    arielatom300heps New Member

    thanks for that info Clotho
    so if u want more performance this is not realy the way to get it.
  15. The issue of increased performance has been touched on many times in this forum over the years. The greatest increase in power on an HT is going to be had with a tuned expansion pipe. It's just not going to be had with a carburetor alone.
  16. wayde

    wayde Guest

    hey good news, i put this carb on and took some time to tune it and it makes a heck of a difference BUT only with the proper boost bottle i noticed no change with no bottle. the improvements include better low end torque higher top speed by at least 8 km/h and a way happier happy time
    so tinker with tuning and enjoy the ride
  17. GTscoob

    GTscoob New Member

    Do you have a link to another site that sells this, or even a name of the carb?