Personally, I've never worried about crush washers, and I've never had anything but a drip or two come from the drain plug. The first one I lost, I had only one vehical, so I reassembled everything and went on my way. Having all intentions to get to the dealler to replace it. Forgot about it untill the next oil change. Afew hundred K miles on many bikes and I don't think its been missed by any of them.
But it must have some engineering significance, or they would not put it on the bike. The real world doesn't seem to care.
But it must have some engineering significance, or they would not put it on the bike. The real world doesn't seem to care.