My bike has been exposed to heavy rain while commuting and at the parking lot of my work place (stormy Florida).
Cables (clutch and choke), main switch and chain are what suffer the most, unless you are a lubrication maniac, as I am.
Water rain can find a way into the gas tank, as happened several times to me and made me drain the bottom before it went down the carbs (it did once).
Electrical connections exposed to splashes on the road may get good contact reduced (has not happened to my bike so far).
Good thing is that the bike stays clean and requires less hand washing.
