Just got a used 66cc slant head

And if you're unfamiliar with the CNS, don't get familiar; invest $20 in an NT Speed carb...it will save you CNS agony.

Looks like you have a 2011 Grubee Skyhawk apparently...

I think you have been given all the proper answers already. It's a good start to have regular nuts on your head studs instead of acorn nuts. I would just check the torque on the head nuts, and recheck it after putting some miles on it. If they are still torqued up I would just roll with it as is, if they seem to be coming loose you might want to upgrade the hardware. I don't know of any white loctite, the removable type is blue and the permanent type is red, so not sure what the white stuff is. At any rate, if the studs hold torque on the head that's all they need to do....

On the CNS carb, some people will say "throw it away and buy NT, RT, Speed carb" etc etc. I don't know why, you would think in a forum dedicated to building your own motorized bicycle people would be more willing to tune their own carb? At any rate, the CNS carb is not useless, its just more complicated and harder to tune. The standard style carb (NT, RT & Speed) have only one jet, the CNS carb has 3, a main jet, an idle jet, and an "enrichment" jet (which is the choke, the other carbs have an air choke on the air filter). The enrichment jet is activated by that second cable, it adds extra fuel to richen the mix to help cold starting rather than choking off air to richen the mix. The idle jet is extremely small and can clog easily, when clogged you may have hard start and rough running at low rpms, so you want to make sure that idle jet is clean. Mine clogged once and I cleaned the carb with carb cleaner spray, it didn't come clean. Second time around I pushed a thin wire through the idle jet to make SURE it was clean and that fixed me right up, I can start my motor with one kick with my bike on the stand running this "garbage" CNS carb... LOL

Another thing that is a little different (better) about the CNS carb is the way it seals on the intake. There is a little black rubber gasket in the neck of the carb, it is not a simple o-ring, it is shaped so it actually fits over the intake tube to seal. (some people mistake the white plastic spacer for the seal, that is just there to physically clamp the carb in place, it does NOT make the seal). I would recommend that you pull that black rubber seal out of the carb and fit it on your intake to get an idea how it fits together. When you mount the carb slide it back until it bottoms out, then wiggle the carb a little and push it firmly until the intake seats inside that lip on the black rubber seal. Then, when tightening the screw to mount the carb, push the carb firmly onto the intake until the screw is tight. If you mount the carb in this manner you should get a good seal, I've never had a problem with air leaks, and never used any sealer on my intake/carb junction.
Post back if you have any problems, otherwise, happy riding!

Not to start a debate, but my first kit was the 2011 SkyHawk with the CNS3. I'm pretty mechanically astute, and considered all the CNS-bashing going on in favor of the NT to be the product of lack of knowledge, or maybe even technophobia. The CNS is billed as a "performance" carb, and is marketed as such in Grubee kits. I learned all I could about the carb, and tuned it to the best of my abilities...exposed the EPA hidden mixture-screw...sealed it up good and tight. It performed well when in tune...but no better than my NT Speed. The CNS was designed for a larger engine...which engine I know not, but it wasn't for a 66cc. There are just too many degrees of freedom on the CNS, and therefore more avenues for it to detune. The fact that Grubee had to jury-rig a plastic-collette to make it fit the smaller China Girl intake is suspect. I have the stock tank-filter and a good inline filter, yet I had to open the CNS a few times to clean out that damned idle-jet. Unless you're meticulous with your pump-side premix, you're gonna eventually get some crap in the carb-bowl...the NT handle it, the CNS is like a whiny girlfriend. The NT is simple, cheap, and highly reliable. Take the advice of someone who forgave his CNS far too many times: NT Speed.

Kioshk said:

Not to start a debate, but my first kit was the 2011 SkyHawk with the CNS3. I'm pretty mechanically astute, and considered all the CNS-bashing going on in favor of the NT to be the product of lack of knowledge, or maybe even technophobia. The CNS is billed as a "performance" carb, and is marketed as such in Grubee kits. I learned all I could about the carb, and tuned it to the best of my abilities...exposed the EPA hidden mixture-screw...sealed it up good and tight. It performed well when in tune...but no better than my NT Speed. The CNS was designed for a larger engine...which engine I know not, but it wasn't for a 66cc. There are just too many degrees of freedom on the CNS, and therefore more avenues for it to detune. The fact that Grubee had to jury-rig a plastic-collette to make it fit the smaller China Girl intake is suspect. I have the stock tank-filter and a good inline filter, yet I had to open the CNS a few times to clean out that damned idle-jet. Unless you're meticulous with your pump-side premix, you're gonna eventually get some crap in the carb-bowl...the NT handle it, the CNS is like a whiny girlfriend. The NT is simple, cheap, and highly reliable. Take the advice of someone who forgave his CNS far too many times: NT Speed.

Click to expand...

First off, get an inline fuel filter, no more clogs... simple.

As for performance, no carb is gonna make one of these motors jump out from under you with power, it is what it is, a little Chinese two stroke. You even said yourself it performed well when tuned. The CNS isn't the only carb in the world with the spacer in the mount, and the throat of the carb is fully open to the intake so I don't know about it being for a bigger motor...

Bottom line, no reason to advise everyone to change carbs when you can give them advise to make and keep their CNS carb run great. Since I tuned mine and added an inline fuel filter I haven't had to touch it, I would say thats been about 1,400 miles.

And BTW, I have read plenty of threads from people posting having trouble with NT, RT, Speed carbs too, none of them are perfect. Choke issues, tuning issue, jetting issues, slides sticking etc. I have a brand new Speed carb sitting here, the slide isn't so smooth on it and it doesn't look to be any better quality overall than the CNS. One day I may throw it on the bike for an experiment, but my CNS just runs great for me so I'm not very motivated to do it...

I said I DID have a good inline filter, . "Quality" isn't a question, in fact I'd wager that the NT has a lower amount of QC than based on its dirt-cheap price. I've ridden a couple of thousand miles on both carbs. I swear by the NT Speed on a 66cc Skyhawk...wouldn't go back the CNS, it's too picky. It's also super sensitive to being level and having its float height set. Plus, if you have the stock air-filter, it'll probably fall off in the first 500 miles when the glue breaks down from the back-blown fuel...happened twice to mine. Which reminds me: the CNS's stock air-filter more prone to fouling which reduces air-flow and performance. The NT's sponge-filter handles back-blown fuel better...allows cleaner evaporation. I'm speaking from experience; enjoy your CNS if it's working for you, but I advise Mr. Black to replace it with an NT Speed; simple...cheap...reliable...and requires less maintenance and easier to tune than the CNS. You'll have fewer degrees of freedom to worry about when tuning your Girl.

I run the cns2 on one of my bikes also, it has performed well. I think nightcruiser runs the same carb also, as he said if it is tuned properly it runs well. My other bike has the nt, it runs good after tuning it also. The one thing I like better on the cns2 is the remote choke, its easier than the right side choke lever on a stock nt.