What should be the biggest worry of all motorcyclists after the raining season has finished; corrosion. Corrosion is the greatest enemy of the outside of any motorcycle, and atmospheric oxygen is the most plentiful corroding agent. It corrodes paint, tires, aluminum, plastic and so on. Oxygen must be kept away from as much of your bike as possible or practical. This is accomplished with various barrier materials.
All the bolts, washers and nuts should at least be plated with metals that are much more resistant to oxidizing. Most motorcycles bolts are zinc plated. Zinc does oxidize slowly and the gray layer of zinc oxide that forms on the surface slows further corrosion. If you polish the gray film off various bolts to restore their original luster, you remove the protective layer of zinc oxide. Do this enough times and you'll polish through to steel and create a more serious corrosion problem.
Some years ago motorcycles had no chrome - just paint and some plating. Then came a time that motorcycle types liked chrome so more and more motorcycle manufacturers started to use more chrome. Chrome corrodes somewhat slowly; however, it tends to be porous. If it were not for the layer of copper and nickel under the chrome, the pores in the chrome would allow rapid rusting. We have all seen pitted chrome from when some of those pores reach the steel and allow oxidation. Good chrome is chrome with plenty of copper and nickel under it; however, even good chrome has some porosity and needs further protection. Also on the modern motorcycles, manufacturers use less chrome then they did in the early 90's.
Other contributors corrode or accelerate the corrosion of the various parts of our motorcycles. We all know about salt. It absorbs water, which then pumps atmospheric oxygen to the surface to which the salt crystals are attached, such as a hot aluminum engine parts. So, keeping your bike protected from these elements can help keep it from corrosion. And please not forget that riding your motorcycle in the fresh ocean air comes with minuscule small salt crystals, even if it not rains.
To our luck more and more motorcycle manufacturers see the benefit of using stainless steel, it easy in fabrication, modern techniques mean that stainless steel can be cut, welded, formed, machined, and fabricated as readily as traditional steels. And stainless steel has a very good corrosion resistance.