General maintenance for bike with unknown history

[Jamesripp]

Hi all,

Just bought a 2001 GZ with 24k miles and I love it. The previous owner admitted to not knowing much about its' service history but the price was right so I bought it anyways (I know it was a stupid newbie mistake but so far its running fine). Lurking around this forum has been great for most questions I've had - I downloaded the manuals but don't have the resources to do many of the things they suggest, so what is the absolute most important maintenance that should be done on a bike of this age/mileage (other than oil and filters - I've already changed the oil and oil filter and installed a new air filter)? Is there any really important maintenance I should do since I just got the bike?

Also I have one general question I can't seem to find a succinct answer to. The engine tends to stumble when idling (firing sounds irregular and sluggish, like its not firing in proper rhythm). I saw one post saying that this is normal, and another saying that this might mean the idle speed is too low, another site said it might mean I need a tune up. Any suggestions?

Thanks!