New CB175 owner, questions...

Greetings!
I recently got my hands on a 1971 CB175 for a song, and I have a couple questions. The bike is in pretty good shape, paint is a bit faded, but only had 4k miles, and fires right up on the first or second kick. The solenoid on the starter seems bad, just kinda stutters and wont turn the engine. No big deal as the kick starter works fine.

The questions I have are this-
I would like to change the oil, how much and what weight is best? It says 10-40 on the cap, but just checking if that is still the best choice. And where is the filter?

The tires have tread, but are pretty dry. I can't find a listing that matches the 2.75x18 and 3.0x18 tires that are on it. What is the equivalent size in metric tires available?
Is there any benefit/drawback to a wider tire in the back? I admit it is purely for looks, but I'd like a bigger tire out back. If its not too bad an idea, what is the widest tire that will fit?

Other than that, the bike is fine. It runs great, and I think I'll just clean it up real well before I decide what else I want to do with it.
Any other recomendations for this bike? I know I need a manual,(looking for one).
Valve adjust?

Thanks for your advice!
Brian

Edited by - barnstormer on May 23 2005 8:39:52 PM