CNS carb. Problems? easy fix

that guy on a bike · Apr 21, 2011

Engine bogging? wont idle right? have gas contantly running out the overflow? If you have a CNS "speed" carb. with the stupid red airbox, and the hoses sticking out everywhere, and you can't get the "performance" you want out of it then throw it away and buy a NT carb. Tryed everything with the CNS and only the NT fixed my bike. dance1

Pablo · Apr 21, 2011

that guy on a bike said:
Engine bogging? wont idle right? have gas contantly running out the overflow? If you have a CNS "speed" carb. with the stupid red airbox, and the hoses sticking out everywhere, and you can't get the "performance" you want out of it then throw it away and buy a NT carb. Tryed everything with the CNS and only the NT fixed my bike.

No one listens to me when I tell them that.

DaveC · Apr 22, 2011

"red box" = red flag. I have one of the V1 CNS carbs and I couldn't be more pleased.

I can't even guess why they changed the design, most likely they are saving 3-4 cents per carb or something like that

bairdco · Apr 22, 2011

pablo, i know what you mean. somewhere buried in one of the very first threads about the CNS carbs "upgrade," i predicted the majority of people would have problems with it.

nothing beats the simplicity of the NT. that's what i'm using on my race bike, and it doesn't sputter, bog, leak, or anything else. it works great.

rohmell · Apr 25, 2011

Looks like the CNS is being foisted upon the MB community due to EPA foolishness and stupidity.

Dave31 · Apr 25, 2011

Mr Don Grubee needs to do the right thing and toss in a working carb into his kits with cns carbs. The kits already has the CNS so the epa would not,and cannot say anything about a spare carb that comes with the kits. Support those Don that support you and your vendors.

The cns carb can be made to work, but its not right that you have to spend all the time trying to get a new kit to run. Plus many just dont have the know how.

The CNS carb is a failure as far as I am concerned.

rohmell · Apr 25, 2011

Grubee wants to play nice with the EPA and them, but when people are going to start to avoid buying his kits because of the included POS CNS carb, then maybe he will know what time it is.

TinkerBuddha · May 19, 2011

I was having the same problems with my latest grubee build when I came across this thread. I had a dicarded HT carb in my toolbox from a seized BGF POS and just bolted it up and WOW! there is just no comparing the two! HT wins! this will cut time off my ride to work! the cable was a bit too long so I had to get creative, but (a little electric tape later) i have the fastest bike i've ever had! dance1

skyhawk66cc · May 20, 2011

I ordered up the NT and it works great, but I figured I would try and get the CNS running as good as I could just for something to do, A little tinkering and a whole lot of High Heat RTV later and its actually not that bad of a carb, has good speed and idles good, But it’s stupid that a brand new carb doesn’t work right without messing with it and putting goop all over it. Way easier to just get an NT. I currently have the CNS on my bike just because, and I have gotten about 200 miles on it with no problems after I messed with it. I still recommend the NT though.

-skyhawk66cc

bairdco · May 20, 2011

if anyone has a CNS they want to send me for free, i'll take it...

i've never tried one, and i love the NT's, but i'd like to get a CNS and see what the problem is. i used to work in a carb shop, and i know carbs inside out, and i might be able to figure the CNS out and solve a lot of problems for everyone else.

i'll even send it back when i'm done messing with it...

shaolin · May 20, 2011

Ive used the first gen cns carb for about 2yrs now and about 300hrs on it and it works great but yes you do have to do minor fixns. First you need to know the venturi principle so you know which way to turn the mixture screw

. And second the cns carb needs to be sealed air tight. Otherwise your wasting your time trying to make your chinese motor sing. Manic mechanic sells an intake for the cns carb that eliminates that leak without even using the nylon bushing. But other wise a good sealant will do just fine. I just like controling my mid throttle response with the mixture screw other than slamming my elbow to my knee to get the main jet to fully work its magic

socialdistortionkid · May 22, 2011

just bought a Grubee GT5 engine kit with the CNS carburetor. It runs fine but you will need to adjust the float level. My bike wouldnt idle so surely enough i tore the carb again to find out that the pilot jet was clogged from the factory! Now it idles fine but im playing with the air/fuel mixture screw and the idle screw.

I dont know why everyone else has problems with this carb it runs fine to me!

Lowandslow · May 24, 2011

I don't agree with the "just throw it in the trash" opinion of the CNS carbs.
My kit came with a CNS red air filter version and I have learned a lot about this carb in the process of tuning the motor. First, it is probably not going to be a plug and play experience. Second, the clamp and plastic bushing IS problematic and a main source for air leaks. So, what to do? Throw it in the trash and get a NT carb if you don't want the hassle. But, if your like me and like to tinker and learn, spending a little time will get it running just fine and you get the satisfaction! Here is what I did to mine. Sealed the heck out of the intake connection with ultra grey sealant. Adjusted the float level. Upjetted by drilling to the next size to get rid of the bogging at full throttle. Adjusted the needle clip. Adjusted the mixture screw. Adjusted the idle screw. Replaced the cheap vent hoses with quality fuel line to prevent kinking of the vent hose(yes this made a difference) Installed a quality petcock and sintered bronze fuel filter.
Replaced the red air filter with a HD chrome filter so no one knows I'm running a CNS carb! It flat out runs now and the idle is great. Just my experience.

socialdistortionkid · May 24, 2011

I would just sell it for $50 because it cost $65 new and take the money and buy a NT carb for $20 and keep the profit. Every time the weather changes you will have to retune so i think its a pain in the a** to keep messing with this Carburetor. The NT Carburetor is trouble free and everyone likes them better.

thunderbolts · May 24, 2011

I just ordered a NT speed carb to replace the CNS piece of crap, I spent week's trying to get it right with no luck. I used my earler NT form a older none grubbee motor and HELLO it made the bike go like my older one. Also while checking for vacum leaks with carb cleaner I found my brand new grubbee sky hawk from KINGS Had a masive head gasket leak so i pulled the head and found the head gasket didnt even fit the head correctly and was crushed when assambled. I took a new gasket and filed it to fit the head so it would not get pinched between the head and the top of the cylinder. I also found the caseing gaskets to be leaking more vacume leaks. Rember this is a new motor from KINGS I agree that the NT carb should be included in a motor kit !!!!! But what about those of us that are stuck with the CNS junk I have two of them , both junk !!!!! my motors are only 3 weeks old and I tried to get KINGS to send me two NT's thay said yes thay would send them out that day!!! That was 2 1/2 week's ago Now thay dont even answer my calls or e-mails "GOOD custemer relations " And there lier's!!!!!!!

socialdistortionkid · May 25, 2011

I probably wont be buying from Kings again because of bad customer service but i payed for a Jet 66cc and got a better quality motor for cheap dance1

.

I think you are doing something wrong if the NT makes your motor run bad, check the float level and clean the carb main jet

kassult · May 26, 2011

I also have the red CNS carb and this is my first motorized bike kit. I generally get engines since i play around with them any chance i get but i don't understand everything since im just graduating from high school. I just recieved another carburetor sleeve since the old one broke (took me over 3 months to just find the stupid part and another few months to have someone actually let me order one) and put it on and my motor instantly worked better. Just a few rides around the block later it starts to bog after just a little throttle. I have been playing around with the idle and fuel/air mixture screws but nothing seems to work. I just want to getting this bike working so i can sell it and put together another for college. So pretty much the whole point of this post is to ask if i really should just get the NT carb. I know its inexpensive but i really dont wanna spend money and would much rather just get this to work now instead of having to wait for a piece to be shipped. Definitely not impressed with my first motor kit. :-||

thunderbolts · May 26, 2011

There should be no need to use the choke or enricher valve,As they call it. If you do there go's your 100 Miles to a gallon and your expelling more emissions!!!! What would the EPA think? Maybe someone should contact them, and tell them about the CNS choke/enricher valve? Hummm, "The light just came on"

socialdistortionkid · May 26, 2011

kassult said:
I also have the red CNS carb and this is my first motorized bike kit. I generally get engines since i play around with them any chance i get but i don't understand anything since im just graduating from high school. I just recieved another carburetor sleeve since the old one broke (took me over 3 months to just find the stupid part and another few months to have someone actually let me order one) and put it on and my motor instantly worked better. Just a few rides around the block later it bogs after just a little throttle. I have been playing around with the idle and fuel/air mixture screws but nothing seems to work. I just want to getting this bike working so i can sell it and put together another for college. So pretty much the whole point of this post is to ask if i really should just get the NT carb. I know its inexpensive but i really dont wanna spend money and would much rather just get this to work now instead of having to wait for a piece to be shipped. Definitely not impressed with my first motor kit.

i bought my NT carb on ebay and it got here in 1 Buisness day. $18.99 shipped priority mail

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CNS carb. Problems? easy fix

that guy on a bike

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Pablo

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DaveC

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bairdco

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rohmell

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Dave31

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bairdco

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