Jetting a CV carb is easy, but the jetting only accomplishes part of the job. You must raise the needle in it's holder to bring in the fuel circuits earlier for added performance.
When adding two #4 washers to the needle in a CV carb, slide them up the needle from the bottom and reinsert the needle in the holder (slide). This will bring in the fuel circuits a bit sooner because it raises the needle up from it's original position on the tapered end and allows the fuel circuits to richen the mixture earlier in the transition as the slide lifts.


Slide Detail

1. Slide spring

2. Spring seat

3. Jet needle

Spacers (washers) go under Clip on needle ( #3 )
Factory needles will have a fixed button on the top and not a clip.


http://i149.photobucket.com/albums/s45/bills985/CVSlidePic.jpg