Re: where to buy screws, etc for my bike
Ace Hardware also carries a good selection of metric fasteners.
I'd shy away from stainless steel for engine mounting fasteners. Side covers, intake and exhaust yes, but stainless isn't a good choice for areas subjected to high stress and vibration. This isn't just opinion but sound engineering practice.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"