XL Sportster Intake/Exhaust Valve Guide, +.003" (OEM/NOS #18131-83C)
Factory references show first use in 1993, and we can confirm use to at least 1998, but we suspect later use is also likely. This part number corresponds to both intake and exhaust guides with a .003" oversize indicated.
We do not have Factory references for 1999-2001. But we do have the 2002 reference, and for 2002 it shows the same part number but with the "D" designation. Therefore, some time between 1999-2001, the Factory changed from the "C" to "D" variations. Generally, a change in letter designation represents some update in design, and the later designations generally supercede previous designations. However, we always recommend you consult your own Factory references and local builder for further technical guidance.
Sold each/individually.