Gearing Questions

Geoff writes in with a few questions on gearing:

I recently purchased my first 1972 Yamaha R5C from a coworker for $100!! (The bike has 11,000 miles on it) When searching for restoration info I came across your amazing site. I am anxious to start riding this beauty ASAP and was looking for a little advice. I am finding that most people start with handling and engine issues. The engine appears to be running well, but I feel I need to replace a few key components (sprockets, chain, brake shoes, etc.) I am having trouble finding concise info on how to gear the bike. Do you have any suggestions on what size front and rear sprockets to use and what type of chain? This is my first street 2 stroke and I will be using it mostly for occasional pleasure riding. Any help or referrals to info would be greatly appreciated!