The frequency of changing motorcycle fork oil can vary depending on several factors, including the type of motorcycle, riding conditions, and manufacturer recommendations. However, as a general guideline, it is recommended to change the fork oil every 10,000 to 15,000 miles (16,000 to 24,000 kilometers) or every two to three years, whichever comes first.
Keep in mind that heavy off-road riding or aggressive riding can cause the fork oil to break down more quickly, requiring more frequent changes. Additionally, if you notice any signs of oil leakage, reduced suspension performance, or a change in fork behavior, it's advisable to inspect and possibly change the fork oil sooner.
Always consult your motorcycle's owner's manual for specific manufacturer recommendations regarding the frequency of fork oil changes for your particular make and model. The manual will provide the most accurate and reliable information for maintaining your motorcycle's suspension system.