How to tune the CNS V2 Carb.
I hope you don't mind Biknut, but I have taken all the information from this thread and compiled it into what I hope will be a quick list for setting up the CNS V2 Carb. to run on the 66cc engine 1000ft above sea level or less. Further testing required for above 1000ft.
1:
Raise the float level.
Turn the Carb upside down. There's a seam in roughly the center of the plastic float. adjust the float till the seam is parallel to the sealing surface of the float bowl.
2:
For the high end, drill out the main jet.
Buy Machinist bits #64 #65 #66 #67 #68 #69 #70 (Stock jet size is #70)
Drill out the jet one size at a time starting with #69 Test and check for full throttle response and spark plug color. Below 1000ft altitude #65 and #64 seem to be about the right
size. If you drill to large of a hole, fill with solder and re-drill with a smaller
bit.
3:
For mid range, adjust the C-Clip on the throttle pin.
(Top is lean and bottom is rich) Again check your spark plug for direction.
Black is RICH, White is LEAN, you want a tan or brown color between.
4:
low end or idle.
The air and idle screws on the side of the CNS V2 Carb are for setting the
idle fuel/air mix. First turn the air mix screw (left) all the way in and back it out 1 full turn. To raise the idle turn the idle screw (right) clockwise, counter clockwise to lower the idle. Now fine tune the air screw where your engine runs at it's highest rpm then lower the idle with the idle screw.
Foot note: In some cases, but not all, removing the breather tube from the air filter may result in better performance.
ps: I will gladly edit this information if I have gotten something wrong, or new information is gathered.