I'm looking for a new carb and I was wondering what the difference between the "Performance" carb that Spookytooth sells and the Dellorto style 19mm you can buy on ebay. I have an expansion chamber from Pipelyne and was looking for a little more performance from my carb. What are the differences and what would you guys recommend? Thanks
New Carb. Dellorto Style or "Performance" carb?
- Thread starter z2400969
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id go with the CNS "performance" one. its a little more tunable than the pocketbike carbs.... i tried one. there are several styles of that dellorto out there and only one of them has a hoping chance of correctly being tuned for our bikes.
go with the CNS, zoom bicycles also has them in stock.
go with the CNS, zoom bicycles also has them in stock.
do you have any tips on tuning them ^ ? i think i have one to pick up this morning at the post office 
It's Easy, There Are Two Mixture Screws One's For The Idel The Other One Is For The Top End. Get It Started And Adjust The Idel Mix, Now Take It For A Ride See How The Top End Is, If It Feels Good Ride It Around Then Ta Ke Out The Spark Plug And See What Color It Is, If It Is White Or Light Tan You Have It To Lean, If It Looks Wet It's To Rich. You Will Feel A Big Difference With The New Carb.
I've gotten great results from the billet intake at Pirates and Creative engineering.
And I've got the new NTS ready to go- which should install in about ten minutes, but just got the muffler replaced today.
Once the billet is used the carb is lowered and clearance for carb length is even less.
So the NTS is shorter than the CNS, and half the cost, and has fuel shutoff valve.
I didn't like the look of the LONGER offset intake needed to clear the CNS carb- The motor ports are bigger than the intakes, and the billet evens that up at least on the motor side. I reamed it slightly more- the alloy files away easily. The carb is then also closer to the motor. I've actually got great performance now from the old stock, so the NTS wil be a little overkill-
But the proof is in the sight lines- Just look through the ports and you can see where the carb restricts the flow- the NTS has larger ports now and the billet puts it right up by the motor which may be an even bigger factor. (The CNS has bigger ports, but the adapter to the intake cuts that down again. They recommend enlarging the ports on the motor- that doesn't make sense, it's still the same size flow through the intake.) I'll probably ream the old stock carb ports a milimeter when the other is on, just for the heck of it. The motor's ports really don't seem to need it.
I'm 2 stroking at will now, but with a 36 sprocket and wheels that roll, I generally don't want to open it up that much!
And I've got the new NTS ready to go- which should install in about ten minutes, but just got the muffler replaced today.
Once the billet is used the carb is lowered and clearance for carb length is even less.
So the NTS is shorter than the CNS, and half the cost, and has fuel shutoff valve.
I didn't like the look of the LONGER offset intake needed to clear the CNS carb- The motor ports are bigger than the intakes, and the billet evens that up at least on the motor side. I reamed it slightly more- the alloy files away easily. The carb is then also closer to the motor. I've actually got great performance now from the old stock, so the NTS wil be a little overkill-
But the proof is in the sight lines- Just look through the ports and you can see where the carb restricts the flow- the NTS has larger ports now and the billet puts it right up by the motor which may be an even bigger factor. (The CNS has bigger ports, but the adapter to the intake cuts that down again. They recommend enlarging the ports on the motor- that doesn't make sense, it's still the same size flow through the intake.) I'll probably ream the old stock carb ports a milimeter when the other is on, just for the heck of it. The motor's ports really don't seem to need it.
I'm 2 stroking at will now, but with a 36 sprocket and wheels that roll, I generally don't want to open it up that much!
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Prefer the dellorto as its high tuneable and i didn't want to remount my motor which is a pain in my 21'' frame in order to use the cns.
im just going to use a copper elbow for my CNS. either that or i will have the millwright at work tool up a 45 tube
Got another question for you Mountain...does the PHBG AS 16mm an exact fit with the stock manifold? and what jet size are you using? did you undergo a lot of testing before you find the right tuning? what are the things that you do....in my opinion and on what I have read in the description dellorto is the best carb upgrade for china's 2 stroke...btw what engine are you using? Thanks
To answer you're questions: NO the phbg series is not a simple bolt on, I machined a nylon bushing in order to adapt it. The id of the carb where it sits was 26 mm and my stock ht manifold OD measured around 0.744'' but I measured everything out with mics and such. By the time I got the carb we were into winter and have not run it BUT their is a rule of thumb that says for every 1 mm increase in carb bore size you must increase jet size 10%. My ported and polished taper bored stock carb ht motor runs a 0.66 mm jet and i am at 4400 feet elev but i also am running 160 psi compression so it uses less fuel.
I am starting with what i hope is overly rich 0.79 mm jet and will lean down from there. Also fwiw the pilot jet from factory are generally acknowleged to be hugely rich, mine came with a 50 pj and i have ordered several al the way down to 35. The engine is a generic ''80"" off ebay which has been completely gutted, rebuilt with new bearings fasteners and a trued crankshaft. Also if you are going to go with the dellorto google the tuning manual it can be downloaded for free somewhere and will be highly useful. Also check out the pics elswhere in the high performance area under first pics with the new dellorto to see how it went together
Cheers
I am starting with what i hope is overly rich 0.79 mm jet and will lean down from there. Also fwiw the pilot jet from factory are generally acknowleged to be hugely rich, mine came with a 50 pj and i have ordered several al the way down to 35. The engine is a generic ''80"" off ebay which has been completely gutted, rebuilt with new bearings fasteners and a trued crankshaft. Also if you are going to go with the dellorto google the tuning manual it can be downloaded for free somewhere and will be highly useful. Also check out the pics elswhere in the high performance area under first pics with the new dellorto to see how it went together
Cheers