That's exactly what I thought about doing. My garage opens up on a grassy lane, so I might just go ahead and do it. I've just taken a trip to my local dealer and got some filters/oil and bought the centre stand too. Guess what I'll be doing tomorrow! There is only the small ring gasket at the bottom of the filter cover and the other bigger one one the inside of the cover AFAIK, and I'm sure I checked they were in place before I closed the cover.