[lord_caffeine]

if the seller won't let u test ride it, walk away.

I don't think that this is good advise. I wouldn't let you ride my bike without you giving me the asking price in cash (see post about stolen bike today).
Ask the seller if he has the maintainance records. Meticulous attention to detail with record keeping will indicate that the bike was PROBABLY maintained well. Check the chain for proper lubrication and tension. If this is good the seller is probably going to do other maintainance as well. Look at the condition of the oil in the window on the right hand side of the engine. Is it black or is it nice carmel brown? When was the last oil change? Listen to the sound of the engine. Does it sound even @ idle? Check the condition of the tires. If you see excessive wear you can take some $$$ off because you will need new tires. Is the bike generally clean?

Anyone else got any good advise for this guy?

 

[lord_caffeine]

How often do you have to get an oil change???

It all depends on how you ride your bike. Trackday guys and racers will change their oil alot more often than every 3000 miles, like recommended by Honda. I usually change oil every 2000 miles or so, depending upon how motivated I am.