I may not be much help here as my K&N filter sits a-top the carb on my
91 syncro westy.

But I have once cleaned the filter and re-oiled it.  I found it not very
messy - but if you do it in the kitchen sink, it is best to do while your
spouse is out for the day.   Note that the directions say to NOT use
soap and water on the filter - only their cleaner stuff.

Malcolm S