The standard oil change cycle on a Harley-Davidson is every 3000 miles. Oil changes usually depend on the riders preference as some owners may wait as long as 6 months before changing their oil.
In order to maintain a healthy Harley-Davidson motorcycle engine, an owner must replace its oil regularly. Failure to do so will result in the oil leaving carbon deposits inside engine's internal components, weakening the engine. The cleaner the oil is, the longer the motor will last.
While changing the oil, the filter should also be changed. The filter keeps debris and contaminants out of the oil while it circulates around the engine. When an oil filter is kept on an extended period of time, it can clog and fail.