exeleration problems

D

deme7695

New Member
skyhawk 48cc. It start fine with the choke on after warming up a bit I start

to ride. It exelerates well until i pull back on the throtle a little more and the

sound becomes muffled and the engine begins to die i let go of the throttle

and it goes back to normal. This happens even with no choke. the bike has

two screws and idle screw and a fuel air mix one. which one do i change or

do i still need to use the choke.
 
it is a CNS carb. But the problem is not when its idle but when im driving.
 

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I have the exact same carb and the exact same problem..still fighting it.
Numerous posts on the new CNS carb and bogging issues. Can't really point you in a direction as I haven't figured mine out yet.
 
Yes, that's one way to solve the problem. I found on my CNS V2 that it was under-jetted and by drilling the jet out (carefull not too much!) that it was night and day. It is currently running quite well and I am very happy with it now. Other things to look for on this carb are the seal at the manifold, check the float level (mine was too low) and also the vent hose for the fuel bowl is prone to kinking and may cause starvation issues. These carbs can be tuned to run well.
 
deme7695 said:
It exelerates well until i pull back on the throtle a little more and the

sound becomes muffled and the engine begins to die i let go of the throttle

and it goes back to normal.
Click to expand...

Sounds like a main jet problem. As long as the needle is down, you seem to be running fine.
When you pull back on the throttle a little more, then you are relying on the size of the main jet more, and that is when your problem happens.
Easiest thing to do is drill the jet one size bigger and see what happens, If the problem gets worse, then you know that you have to solder the jet shut and try redrilling with a smaller hole size.
 
I'd say drill the main jet one bigger. Thats what I did and it helped greatly. I can now cruze around fine , just can't get it faster than 25. It has good exeleration just low top end. I had the same problem and tryed everything. This helped the most. You could also seal around the intake and clamp. I took the spacer out of the carb. Used a high heat sealant and coated the outside of It. slid that back in, put the carb on, sealed around the nut and bolt , tightened it then beaded around everything. Also I port matched the intake gasket to the intake, and the exhast too. Try slightly bending the float tab little bit to see if that has any change. My idle is .75 of a turn out. Air mix is 3.75 turns out and my needle clip is at the second spot. Hope this helps. I'm getting ready to order a NT carb. Probly tonight.
 
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