POS CNS Carb...need an NT?


recon chris

New Member
Apr 28, 2011
pacific grove
I’m new to the world of motorized bicycling in fact I just finished my first build. I took a Rolly M50 and fitted it with a sky hawk G5 66cc engine. To fully understand what I’m going through I originally ordered a 49cc JET engine kit that would have come with a plain old NT carb but because i ordered the kit from KINGSMOTORS.COM also known as GASBIKES.net also known as THE ASIAN SWINDLE SHOP (i made that last part up due to their complete lack of customer service and common 5 week delivery waits.) they gave me the G5 66cc.

At first I thought "wow this is great i got a better engine for a cheap engine price." and then i installed it... To be fair the engine part if the G5 is fairly decent I have just went through my first gallon of gas and it hasn’t exploded yet so I considerer that a win compared to the stories i have heard on this forum. With the engine part being good the carb is something else.

That CNS carb is the biggest piece of S&#t that has ever been my displeasure to deal with. Fist I installed it with the factory settings it came with.

This was a failure...you can’t actually install it the way it comes, there is such a weak way of connecting the carb to the intake spout that it is GARENTEED NOT TO BE AIR TIGHT even when you add high temp silicon engine sealant. And then even if you manage it get it air tight the carb will literally vibrate off the intake spout GARENTEED no matter how hard you tighten it on. (I’ll go to Vegas right now and put my life savings on it if they were dumb enough to bet me)

The second attempt was to seal it by taking a large steel hose clamp and clamping the carb to the spout by wrapping the clamp around the back of the carb and the front facing part of the cylinder body. This is the only way I found of successfully connecting the carb with the engine and yes in this orientation it seals air tight......not like that makes a difference with this POS.

The CNS carb is what I would expect to get if I sat 15 engineers in a room around a pink eraser and said to them "make it better" It is so complicated and redundant in design that you would think atomizing fuel was the work of rocket scientists.

Let’s start with the choke. Regular chokes restrict the air flow by sliding a plate in front of the intake port WOW how simple does it get. The CNS choke doesn’t do that, in fact moving the choke to the on or off position affects nothing about the main air intake port. Instead it involves a:

connection plate
Cable (extending to handle bars)
Sheathing (for cable..won’t work without it)
Pot Metal actuator
Plastic actuator position holder
Screw (tightening position holder together so it holds position...this vibrates loose constantly)
Handle bar connection clamp and screw
AND custom led fighting for the end of the cable to attach to the plunger

And what does all that do??? CHOkES THE F#@$ING ENGINE!!

On top of that you have the "RED BOX" air intake, and if you think for one second that it actually "SCOOPS IN AIR" your absolutely wrong. I have gotten more reliable and more consistent results with it completely off because the carb likes to spit oil and fuel back up into it making air actually have to RESTRICT to pass through it.

And then you have you hoses and tubes. Oh the hoses, the hoses that vent the bowl the hoses that vent the main jet intake all of which have to be tucked inside the Red Box intake to be protected from dirt. And the brass tubes that vent everything else twice and three more times just to make sure.

But no; it’s all ok if it works right? Well here is how it works.

After cleaning every millimeter of the carb properly (yes even the Jets) it fails at delivering ample amount of fuel to the engine. So I adjusted the fuel needle clip down to the second from the last notch PRESTO NOW I CAN ACTUALY MOVE UNDER LOAD AND NOT JUST LEAN REV TO MY HEARTS CONTENT!

Ah but now this is where the carb really fails you.

The engine is powerful enough yes but no smoke is coming out of the tail pipe? That’s weird being as this is a break in mix of gas 28:1 this can only mean that its RUNING DANGEROSLY LEAN!!! I’ll just lower the needle clip down a notch.

Great now it chugs and sputters and drowns the plug in fuel...tits. Well ill move the clip up a notch and fiddle with the air fuel mixture screw.
Fantastic if I screw the mixture screw out it runs a WOT with no power in its stroke. Let me turn it down.

Fantastic now it runs (still totally smokeless) but only if the choke is "in" and the second I let it out it will kill the idle......................

YADA YADA sorry for making such a long thread but I had to vent. This is what I have been going through the past five week. One smokeless gallon of fuel later and I think I have successfully broken the engine in the hard way.

So what do you guys thing will I get the same stuff with the NT carb or will it be a install and forget deal, because this CNS carb makes motorized biking absolutely NOT WORTH IT.


New Member
Aug 31, 2010
New York
I've been in the toss up of deciding to get the CNS. But from what I've read I'm not going with it. I'm gonna go with the speed carb, billet intake, and an air filter


New Member
May 11, 2011
It seems to be a pretty common theme that everyone hates the new cns gen B (red cover) carb. In my experience it hasn't been to bad...Other than trying to find jets for it of course. Mine also had a pretty big air leak where it clamped onto the intake, but some black silocone fixed it right up. Mine runs pretty well to about 3/4 throttle and bogs out a little (too rich). I did manage to find jets throught Dellorto Direct, they havent shown up yet, but once they do this thing should run like a champ! I'll keep you posted...


Active Member
Jun 2, 2010
New York
I am not a fan of any carb that I have to slather RTV all over it to seal up air leaks, if that is the norn, then the RTV should be supplied with the carb.
A simple NT carb is the solution to all your carb problems. You can get one for about twenty bucks, give it a whirl.


New Member
May 25, 2011
Stony Plain, Alberta, Canada
golly you're persistent. my stock carb lasted a week and then I converted to a pumper style walboro carb that I bought used from a chain saw shop for 20 bucks. I was able to drop to a 35 tooth sprocket, and now I ride with the cars.


Well-Known Member
Sep 28, 2010
Does this sound familiar? I just test started a brand new Grubee SkyHawk 80. It started ok but took a long time before it would run without the choke. Then it would barely run, and if I gave it any throttle it bogs and tries to die. After it warmed up the idle was racing but that was about all.

Seems like it might have a intake leak even though I was careful when I installed the carb.


New Member
May 14, 2011
Orange County, CA
My Gt5 with the CNS isn`t a piece of crap it just needs some work out of the box to make it work right:

1. The screws are set from factory in China, mess with the idle speed and Air/Fuel Mixture Screw.

2. Set the float level so the engine will get enough gas.

3.Rejet. (If spark plug isnt brown)

I also needed to use carb cleaner on the pilot jet (it was clogged) because my motor wouldnt idle.

I like the NT carburetor better, I would sell the CNS Carburetor for like $40, buy a NT for $20 and use the extra money for gas. NT carburetor is troublefree it doesnt need adjustments
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New Member
May 25, 2011
Stony Plain, Alberta, Canada
The stock carb is very hit and miss. The easiest solution is to order a Delorto 16.16 from Delortodirect for about $75.00. It bolts right on, comes with an air cleaner and will never give you a moment of grief. You will also need to order a few jets #52,51 and 50 will likely get you right.