CNS Carb. Question.?

[mapbike]

I just ordered a CNS carb. from Spooky Tooth, when I get it, is there anything I need to do to it before I put it on my motor?

I've had it with the NT carbs, got three of them and can't get any of the three to run right on my engine, I know most people run the NT's with very little issue and that is good if you have a good one but mine have never been any good from the very begginning, got them off E-bay from BGF maybe thats my problem with them just got a bad batch maybe, tired of messing with the blasted things so...... I figure I'll go with an upgrade that at least has an adjustment so maybe I can get it dialed in.

Thanks in advance for any input.

 

[Venice Motor Bikes]

I think Sportscarpat nailed it when he responded to you on the other CNS thread... "if you've had the same problem with 3 new NT carbs... the problem is probably not in the carbs!" You should check for other problems instead of the carb.
If you can't get your engine to run right with the simplest carb on earth, you're gonna have a lot more trouble with a more complicated carb.

 

[mapbike]

I think Sportscarpat nailed it when he responded to you on the other CNS thread... "if you've had the same problem with 3 new NT carbs... the problem is probably not in the carbs!" You should check for other problems instead of the carb.
If you can't get your engine to run right with the simplest carb on earth, you're gonna have a lot more trouble with a more complicated carb.

Ive been rebuilding and tuning carburetors for 25+ years for myself and others on every kind of engine you can imagine and I think the simplicity of these carbs isnt a good thing but instead the problem with them, NO ADJUSTMENTS.....! reminds me of a Tecumseh OHH60 engine and the carbs on them no adjustments and aint worth messing with most of the time. BUT HEY I'M PROBABLY WRONG AND IT'S MY ENGINE AND NOT THE CARB......IT IS VERY STRANGE TO HAVE THREE BAD ONES.....? ~/)

That said, I think my primary issue is like you said something beside just the carb and that problem is, that the engine I have vibrates like a freaking jackhammer @ half up to full throttle, it shakes the carb to death to the point that the needle is bounced in the seat which I believe is what is allowing the fuel overflow in the bowl which causes the flooding issue. I have an extra engine that has never been installed and that is my next step, I'm gonna put it on my bike and put the same carbs on it and see what happens if it vibrates out of itself I think I will have the same issues but if the new engine runs smooth enough not to jackhammer the carbs like this one does then just maybe I'll have a winner.

I will be sure to make my results known as soon as I get it done, Thanks for the input, I have found nothing but loads of helpful info. on this forum and I appreciate everyone that has commented on my questions, I have no doubt that I will get to the end of this issue and will have learned a lot in the proccess, this bike of mine is gonna run if it kills me......! :~{}

 

[michaelgrav]

I recently installed a CNS carb on my PK 80. The manifold that comes with it stinks, so I purchased the billet manifold from Pirate cycles. There are 5 adustable spots for the needle valve. I have mine on 3rd from the top. Fuel Air all away in then out 1 turn, Need to use some Gasket sealer on both sides of the manifold gasket and I used a lil on the carb end also. It runs great!

 

[Venice Motor Bikes]

Ive been rebuilding and tuning carburetors for 25+ years for myself and others on every kind of engine you can imagine and I think the simplicity of these carbs isnt a good thing but instead the problem with them, NO ADJUSTMENTS.....! reminds me of a Tecumseh OHH60 engine and the carbs on them no adjustments and aint worth messing with most of the time. BUT HEY I'M PROBABLY WRONG AND IT'S MY ENGINE AND NOT THE CARB......IT IS VERY STRANGE TO HAVE THREE BAD ONES.....? ~/)

That said, I think my primary issue is like you said something beside just the carb and that problem is, that the engine I have vibrates like a freaking jackhammer @ half up to full throttle, it shakes the carb to death to the point that the needle is bounced in the seat which I believe is what is allowing the fuel overflow in the bowl which causes the flooding issue. I have an extra engine that has never been installed and that is my next step, I'm gonna put it on my bike and put the same carbs on it and see what happens if it vibrates out of itself I think I will have the same issues but if the new engine runs smooth enough not to jackhammer the carbs like this one does then just maybe I'll have a winner.

I will be sure to make my results known as soon as I get it done, Thanks for the input, I have found nothing but loads of helpful info. on this forum and I appreciate everyone that has commented on my questions, I have no doubt that I will get to the end of this issue and will have learned a lot in the proccess, this bike of mine is gonna run if it kills me......! :~{}

Post some pics of how your engine's mounted... lets see if we can figure this problem out??

 

[mapbike]

Hey guys I got my bike running much better now took one of the NT carbs and soldered the main jet up and redrilled it with a #73 bit still got a little sputter and bump at mid throttle but is reving pretty good now, I could get a #70 bit through the jet before I soldered it and actually I think I could have drilled it a little smaller than the #73 and it would have still been OK I just didn't want to lean it out to much only got about 20-25 miles on this motor.

Man the spark plug boots on these things stink real bad, I've had 2 of them crap out on me a few miles from the house today, but I will have that fixed tomorrow, gonna put an accel 7mm copper core wire on it with he good accel silicone boot, gonna have to replace both of my back engine mount studs tomorrow as well, about 6.5miles from the house today and one of them broke off and that was after my clutch cable broke about a mile back from there, man I was just limping this thing back to the house this evening, but I know now why I have read many times how important it is to replace the soft weak studs on these motors, anyway I'm learning a lot about how to make these little cheap made engines run right and stay together, although a real pain sometimes it is very addicting and fun at the same time, below a pic of the prototype bike I'm dealing with right now, I'm working all my bugs out on this one and when I get this engine running the way I want it to I will be putting it on a new Schwinn LINK 21 speed I bought a few weeks ago, then I will be riding this things about 16 miles one way to work and back this spring and summer on the good days.

Thank you all who have put up with my questions and helped me dig down and figure the carb issue out on this bike thus far. Shan

 

[Nashville Kat]

Get the billet intake mentioned above- less than $15- for NTS- you may have clearance issues either way to resolve with a CNS-

before the holidays I ordered the billet intake- reamed it a little further, and it puts the carb right up by the motor port, but lowers it closer then to the sloping seat tube- I also got a new NTS 66 carb with the shut-off valve-

but to test independently, and see what accomplished what, I first put the billet on my old stock carb- it just ran really well right off!

I'm just getting rolling again after winter, and still haven't installed the 66 NTS- "if it ain't broke" etc. etc.

I will be installing it though- if only for the added shut off valve- and it may run better- although I have no complaints with the old stock now- except it leaks gas if I don't close down the petcock when I stop.

 

[mapbike]

Yea I know what you mean about the gas leaking, I have three NT's and they all do it, I had all kindas of heck with mine until I soldered and drilled the jet with a #73 bit, mine all ran way rich and I think I can probably take the one I'm running now on down a little more and it will just do better, still getting a pretty good flutter ouy of it when on flat ground at about 3/4 throttle, statrt up a hill and WOT runs like a champ very smooth without a single sputter under a load. I need to get me the billet intake as well I'm running the little stock Aluminium intake right now.

 

[Nashville Kat]

Actually I got mine pretty much stopped- solution? Gasket sealer around the screws.