Guess i shouldve done some more research on this carb before i bought it. i bought it because i thought it had a idle screw and an air mixture screw (separate) i guess i was wrong. anyways, i noticed it started on the first turn over literally every time and provided a bit better acceleration, but it wont even go past 30kmh? i took it apart to see if i could richen/lean the mixture but there seems to be no way to tune this carb for it to work right/fast... what the hell? did i make a big mistake buying this or is there a way to make this worth the purchase? put stock carb back on and huge difference in top speed and higher rpms run better... getting almost 65kmh easily with the stock carb.. whats going on here? could i at least use the jett from the cns to enhance the stock carb? only reason i bought this carb was to get a bit better torque and power.
CNS performance carb?
- Thread starter nashy10
- Start date
HeadSmess
Well-Known Member
- Local time
- 2:28 PM
- Joined
- May 17, 2010
- Messages
- 3,048
same old same old. throw on another part without doing any research.
yes, you need to do more research. its called "jetting"
the carbs ARE adjustable, its just via a drill-bit and often some solder, not by twiddling a screw
with some luck the jet from the stock carb might just fit the new carb and be the right size, too! iunno. if its M5 it will work. dont waste my time with these "performance carbs" seeing as a straight venturi with simple needle valve would suit my riding...WOT all the way. who needs smooth transition and throttle response on a pansy lil engine such as these things? its not like they will pop wheelies and flick you off into the weeds...
yes, you need to do more research. its called "jetting"
the carbs ARE adjustable, its just via a drill-bit and often some solder, not by twiddling a screw
with some luck the jet from the stock carb might just fit the new carb and be the right size, too! iunno. if its M5 it will work. dont waste my time with these "performance carbs" seeing as a straight venturi with simple needle valve would suit my riding...WOT all the way. who needs smooth transition and throttle response on a pansy lil engine such as these things? its not like they will pop wheelies and flick you off into the weeds...
the cns is a awesome carb, mine is tuned almost perfect i had to go with a lot bigger main jet and a bigger idle jet. my engine is built to the tilt 3 transfer port added, ramped and windowed piston, balanced my crank, exhaust and intake port work and case to cylinder port match. i also fit a yz80 dirtbike expansion chamber on it so it needs a lot more fuel.
When i first put the carb on with out doing anything it would basically only idle and would bog with any throttle input telling me it needed some jetting. learn how to read your spark plug, once you get the jetting close you can read the plug to fine tune it to perfection.
Your cns carb does have a air/fuel screw and a idle screw, the air fuel screw is hidden under a brass cap that you need to pry off. at the end of the day the CNS is a way more tuneable carb than the stock and will perform better, there is one vent tube you need to block off aswell.
Post a pic of the carb of both sides so i can tell what generation it is.
When i first put the carb on with out doing anything it would basically only idle and would bog with any throttle input telling me it needed some jetting. learn how to read your spark plug, once you get the jetting close you can read the plug to fine tune it to perfection.
Your cns carb does have a air/fuel screw and a idle screw, the air fuel screw is hidden under a brass cap that you need to pry off. at the end of the day the CNS is a way more tuneable carb than the stock and will perform better, there is one vent tube you need to block off aswell.
Post a pic of the carb of both sides so i can tell what generation it is.
Okay on the last pic u posted the picture of the side of the carb where the idle screw is. Too the left of that is your air fuel screw its under that brass cap so find a way to pry it off it is a thin brass cap. Also those 2 vents on the carb u have 2 hoses on, one needs to be blocked off i dont remember which one ill look when im home. If it bogs you need a bigger main jet
I'm with a #68 main jet now it's too lean i've buy #70,#72,#74,#76 main jet from Sickbikepart i'll try those .
If possible I want to know which vent hose need to be blocked mine is all open and it run well .
With this carb i'm not limited in RPM because more flow come from so i've gain some rpm using it instead of NT carb less four stroking too .
I'm using the NT needle because the CNS v3 as only one place to put the e-clip.
Next week i'll received my new jet and I will comment on that here I think it will be better.
THE CNS stock MAIN JET is just too small too use cause WOT to bog and stop the engine because it's too lean.
I want to know where to find a good IDLE jet for the CNS too .
If possible I want to know which vent hose need to be blocked mine is all open and it run well .
With this carb i'm not limited in RPM because more flow come from so i've gain some rpm using it instead of NT carb less four stroking too .
I'm using the NT needle because the CNS v3 as only one place to put the e-clip.
Next week i'll received my new jet and I will comment on that here I think it will be better.
THE CNS stock MAIN JET is just too small too use cause WOT to bog and stop the engine because it's too lean.
I want to know where to find a good IDLE jet for the CNS too .
Fabian
Well-Known Member
There is nothing wrong with the standard NT carburettor. It just needs to be jetted correctly for your environmental conditions.
In my opinion the Walbro style (diaphragm) carburettor is the best option because it allows you to adjust the air/fuel mixture with external jetting screws. A secondary benefit is that a diaphragm carburettor does not suffer from air leaks of fuel leaks. They just work!
The premium option is to combine a diaphragm carburettor with a reed valve intake system; getting more and less and none of all of the things you want: more low and midrange rpm performance and less intake noise, and without any fuel and/or air leaks.
In my opinion the Walbro style (diaphragm) carburettor is the best option because it allows you to adjust the air/fuel mixture with external jetting screws. A secondary benefit is that a diaphragm carburettor does not suffer from air leaks of fuel leaks. They just work!
The premium option is to combine a diaphragm carburettor with a reed valve intake system; getting more and less and none of all of the things you want: more low and midrange rpm performance and less intake noise, and without any fuel and/or air leaks.
D
Deleted member 12676
Guest
yeah but doesn't the Walbro need a hose running to a nipple you have to install on the cylinder to access the crank pressure/vacuum?
If so then I don't consider it a good option.
Get a Mikuni or Dellorto carb
If so then I don't consider it a good option.
Get a Mikuni or Dellorto carb
Fabian
Well-Known Member
Jaguar, you know very well that a diaphragm carburettor needs a crankcase pulse signal, and that plumbing a signal line from the crankcase to the carburettor is a fairly simple task.
Why would you waste your time with a float style carburettor when a much better option is available, especially if you are in the process of installing an aftermarket carburettor.
Next to fuel injection, the diaphragm method is the next best option.
Why would you waste your time with a float style carburettor when a much better option is available, especially if you are in the process of installing an aftermarket carburettor.
Next to fuel injection, the diaphragm method is the next best option.
