On the primary Choke type as in the CR-SPECIALS
offered by SUDCO the Needle Jet is part of the
Nozzle Holder. KEIHIN offers a Screen Type and
Flat Tyoe of Needle Jets. However, the Flat Type
comes standard in all CR-S from SUDCO. We have
found both street and racing applications that the
Flat Type is more eficient in the CR-S carburetors.
In any case, the Needle Jet is not a calibration parts
and jetting should be done by changing the Needle
The Needle has four factors:
1. Straight portion diameter (D)
2. Clip step
3. Straight portion length (L1)
4. Taper (A)
The inal low is metered at the opening between the
Needle and the Needle Jet.
Y7 2.775 A1 = 0°50’
Y and YY Needles are available in .01mm diameter
increments. YY is 2.7mm longer than Y.
Richness at Starter Valve
“ON” is adjusted by the
CR Special Racing Carburetors