Wix 33006 Fuel Filter
Oil filters, and their selection, can be a mystery to us since we are not able to see how or how well they are working without getting very dirty, hooking up a bunch of instruments, and doing extensive testing on both the filter and the oil.
Understanding how the oil filter works with the oil pump to provide the engine with an adequate oil pressure of relatively clean oil at all times is the first step in knowing what filter to use.
Most importantly, it is more important to have the correct oil pressure and flow through the engine at all times than having the cleanest oil possible.
Motorcycles use what is called a full-flow oil system. Assuming that the oil pump is properly spec'd to exceed the needs of the engine at any given rpm, the oil filter must clean the oil without interfering too much with the oil pressure and flow.
Since the filter works by forcing the oil through a filtering medium, some measure must be taken to ensure that the pressure loss in the filter does not exceed what margin the oil pump has over the pressure and flow requirements of the engine.
If the pressure between the engine and the filter ever drops below the pressure between the pump and the filter by an amount over the PSI setting of the bypass valve, then the valve opens, allowing oil to bypass the filtering system, and balancing the oil pressures.