Hi Whats the very best oil for my 07 450? Does it have to be 10-40w. Why not say 0-50w or 0-40w or 05-40? Do i need to order a copper 'sump plug washer' when ordering a new oil filter? Any nasties or anything to worry about whilst changing the oil over? The bike has been idled / revved for about 15 minutes from new, so i figured it would be a good time to swap the oil over. I was wondering about using mobil 1 fully synthetic oil... if i can find some. The cylinder head is very noisy- is that normal on a new bike? thanks for your time.