New "racing" carb bogging down

I had the same problem with a Superrat engine. I discovered that if I would open and close the choke that it would run good,teling me that it needed more fuel, so I drilled the main jet out to a 72 size and raised the needle as for as it would go.It would then run much better but still acted to lean.But doing a plug check showed a very wet plug and the top of the piston was a black mess also. I tried lowering the needle and it wouldnt run right. So next I checked the timing and discovered it was 43 degrees advanced! That explained the popping sounds I heard at start up. I set the timing to 22 degrees and its a new engine.It starts right up and pulls good to top rpms. So I would check the timing first. I moved the needle back to the middle and the plug and piston top look good now. This might not be your problem but worth checking.

I used a timing light and degree wheel to verify where the timing was set.I removed the key and rotated the flywheel back to get 22degrees.I just used the star washer and nut without the key to hold the flywheel on for testing.I tried different positions but it ran the best at 22 degrees. It turns out that I moved the flywheel about 1/2 the width of the key so I have ordered a offset key to use.The flywheel did not move during testing however.From now on I am going to check the timing on these engines first because you will never tune one if the timing is way off.Once the timing is right make sure the carb is sealed to the manifold so there are no leaks. Another thing my cns carb came without a gasket under the top cover so I made one for it. Also check the head gasket for signs of leaking. Once all this is right then it is a matter of jetting the carb right.

I never got mine to work, utter and complete junk. Swapped back to the standard and its been fine ever since.

I think those carb are defected, 3 of my buddies tried them none of them work they bog flood ect. I went back to the speed carb, and its running it's ass off. we have built at least 20 bikes always trying to improve, do not use this carb...