Hi, I am an old Brit, 74, and rode a small Honda through CR last year on my way south to Tierra del Fuego (http://www.simongandolfi.com) and hit the Blog button. No problems other than taking a dumb fall on a gravel road on the Nicoya peninsula and having my hand stitched on a restaurant table. All the people I met were helpful and hospitable.
I asked a cop in Quito, Ecuador whether the city was safe. His answer serves for any place: Don’t walk at night in dark streets in poor areas of the city and don’t flash money and cameras and gold watches. I would add: Be courteous and dress according to the local mores. Have fun (you will), enjoy and take care.