Here is a thing I use on all my vehicles: get a rare earth (neodynium) magnet that fits inside the round recess in the Majesty's oil drain bolt head. These magnets are amazingly strong. Will cost about $2. Since this bolt is threaded into aluminum and at the bottom of the crankcase this will attract a lot of the steel debris that gets in your oil - you can wipe it off with each oil change. Think all that debris gets filtered out by your oil filter before the oil gets to your engine? There's all kinds of ways oil bypasses the filter. In a overhead cam cycle engine one of the main ones is the cam chain drive. The cam chain is driven off the crankshaft - which picks up LOTS of oil from the wet sump - called windage. The cam drive chain takes this unfiltered oil directly up to the top end of your engine.