If a dog doesn't show sympthoms of rabies does a bite from it pose a healthy risk?

Rabies risk: Yes! It's quite possible that the dog poses a risk. Unless you know the dog and can verify its vaccination status, and/or have the dog evaluated by a vet, then you should definitely receive post-exposure treatment for rabies as soon as possible. Don't delay.

Rabies: Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The vast majority of rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats, and foxes. http://www.cdc.gov/rabies/index.html