From the S&S® California X-Wedge™ Engine Owner's Manual:
Engine oil is a major factor in the performance and service life of the engine. For operation in ambient conditions over 35º F use 20W-50 and for operation in ambient conditions below 40º F use 10W-40.
S&S recommends Mobil 1 20W-50 V-Twin oil is used in ambient conditions over 35º F.
NOTE: S&S recommends regular oil changes every 1,000 miles if using a petroleum-based oil not specifically formulated for motorcycles."
