2012 Harley-Davidson Street Glide — Owner's Manual
In colder climates, the engine oil should be changed often. If motorcycle is frequently used for trips less than 15 mi 24 km , in ambient temperatures below 60 °F 16 °C , reduce oil change intervals to 1500 mi 2400 km. Motorcycles used only for short runs must have a thorough tank flushout before new oil is put in. The tank flushout should be performed by an authorized dealer or qualified technician.
NOTE: The further below freezing the temperature drops, the shorter the oil change interval should be. Water vapor is a normal byproduct of combustion in any engine. During cold weather operation, some of the water vapor condenses to liquid form on the cool metal surfaces inside the engine. In freezing weather this water will become slush or ice and, if allowed to accumulate too long, may block the oil lines and cause damage to the engine.
If the engine is run frequently and allowed to thoroughly warm up, most of this water will become vapor again and will be blown out through the crankcase breather. If the engine is not run frequently and allowed to thoroughly warm up, this water will accumulate, mix with the engine oil and form a sludge that is harmful to the engine. Motorcycles with a Twin Cam 103 or larger engine are equipped with a factory installed oil cooler. Always keep the cooler clean and free from dirt and debris.
This will help maintain maximum cooling efficiency.