CNS Carb

Discussion in 'Performance Mods' started by CPC, Apr 12, 2009.

  1. CPC

    CPC Member

    Ok, I want a CNS carb from spookytooth, Does anyone have one? What kind of proformance gains did you see vs the stock carb?

  2. Shadeslay

    Shadeslay Member

    I have had one for a couple days now and it goes between a love/hate. When I can get the bike started it's awesome, more power top and low, sounds nice and runs great. However, getting the bike started with it on has been a nightmare, 30-40+ kicks vs 1-3 for the stock carb. I'm going to keep playing with it, because like I said it's awesome when the bike is started.

    Really though I'm running out of ideas on what's problem. I was hoping to solve it today, but I'm not sure. Broke a pedal trying to kick it over so much "very cheap pedals, but still". Bright side I'm getting a good workout.
  3. Shadeslay

    Shadeslay Member

    Update, think I have it running good now, I need to give it gas when starting. Here I was thinking it was flooding because the plug was wet when I would check. Also was playing with the open ports, tried closing them but it wouldn't idle well at all. So I drilled some holes into the air filter to run some tubing from the ports into the air filter. Which should keep water and debris from getting into the carb.

    Of course the carbs all out of tune now, but I'll get it back to how it was or better.
  4. fetor56

    fetor56 Guest

    Encouraging....please keep us posted. :grin5:
  5. Shadeslay

    Shadeslay Member

    Well I've tested it out several times now, it's running good, starts up on the 1st - 3rd attempt "if I give it gas". It's mostly dialed in now, the hoses from the ports running into the air filter work great.

    Got the choke working better by letting some slack out of the cable.

    Dialed in the air/fuel by turning it in all the way in, then turning out 1.5 turns. Warming up the engine then turning the air screw until I reach the highest rpm. Turned the idle down, tested using closed-to-1/4 throttle response, until I got the snap I wanted.

    Basically used the instructions here for tuning the air/fuel, needle adjustment and jet size. I lucked out according to that site my main jet is just about perfect. For reference I have a 50cc at sea level.
    Last edited: Apr 25, 2009
  6. fetor56

    fetor56 Guest

    I'm pleased that it's worked-out for ya.Many ppl seem to give up & go back to the old carby,or stick with the CNS & not have it running right.
    One last thing man,post pics. :cool:
  7. Shadeslay

    Shadeslay Member

    Sorry no cam for pics. :(

    I may have actually spoken too soon about the carb. It runs great with it on, but I'm getting some funky coloring on the spark plug and I have no idea how to call it. The tip is white, the porcelain part is tan and the metal part around the porcelain is black and oily "3 readings all the same". I've tried lowering the clip to the richest setting and there is very little difference. I actually get the biggest difference from closing the open ports, but then it doesn't run that well. It can't be the jet it's way bigger then my stock. Tired changing needles etc. I'm fairly certain the open ports have something to do with it, when closed off they make a good vacuum seal, so it might just be getting to much air.

    For now I've gone back to the stock, because I just want to ride and I don't want to chance seizing the motor. But I haven't given up "I just need a break", next thing I'll try is simply playing with the open port sizes. :hammer:
    Last edited: Apr 26, 2009
  8. nadroj

    nadroj Member

    You need to plug those open holes lol, your bike is running very lean!
  9. Shadeslay

    Shadeslay Member

    Ya I've tried that, but it wouldn't idle well at all, RPM's were all over the place. Not to mention the throttle was a bit unresponsive. And the only way to keep the engine from dying was to adjust the idle way too high. On the instructions it says too leave those ports open and with them open it runs great but way too lean. The funny part is when I moved the needle down to a richer setting, it performed like it was too rich, even though I showed no real improvement on my plug.

    I admit it is confusing me why it doesn't work as well as a stock carb when the ports are closed. And I haven't played with it since, but it's something I will sooner or later. I do think a happy medium can be achieved making a well performing carb and not running to lean by restricting the amount of air to the ports.
  10. cspaur13

    cspaur13 Member

    i hated mine. i would give it to u. its a waist of money. your stock carb is better. no performance increase. i think it contributed to my engines early life of about 350 miles. i was probally running it 2 lean cause of that stupid carb. get the sbp air filter that goes on the stock ht carb. that you wont have that cheap chinease 1. it dosent lok like it dose much filtering
  11. rorteg2

    rorteg2 New Member

    I bought one a few weeks back i installed it on my 48cc engine with a definite performance increase. I did have to goto a smaller jet size, because of the cylinder work i did. I opened up the scavenger ports, also did some intake and exhaust port work, also added pipe and silencer from ddm racing. Still not dialed in at WOT, vibration is minimal compared to stock carb.
  12. biken stins

    biken stins Member

    I like mine. The CNS is built for engines that are ported.
  13. jlebh1

    jlebh1 Member

    I bought one awhile ago from zbox in australia and tryed every setting and tryed tuning it and only got a little bit of aceleration and bogging top end im going t try some bigger jets and see how it goes.