I recently picked up a second bike, 2002 gsxr 750. The bike has been standing for a while, parked outside not being used. probably like 5-6month and the chain is all rusty.
Is there still hope for that chain? how do i get the rust off?

 

Provided to "O" rings are not perished (????????!!!!!) you need to clean the chain with kerosene, get rid of all the junk old lube & has a lubricant quality, I use a soft toothbrush very gently, wipe it with rag, and then apply chain lube & then reapply , make sure your getting in to the rollers, Then ride it down to the bike shop & buy a new chain.

 

I wouldn't chance it, get a new chain.

 

if you do want to chance it....

I got some Tiki Torch oil from Walmart (close enough to Kerosene). And a pack of Medium toothbrushes. Clean the hell out of the chain, getting all 4 sides. Do it twice if need be. Make sure to wipe away with a cloth as you go.

Now thats its clean, time to inspect. Take your time and inspect every link, starting at the master link. Check the orings and make sure they are rotted out, and check the round rollers in the center to make sure they spin freely. I'd say if 1 in 8 rollers is stuck then you should be ok. If you find a stuck one, try cleaning it some more. Assuming everything passes, get a good chain lube, I use Honda's HP Lube, and lube it up. Set the tension of the chain, then take an actual measurement of the free play you leave (about 1-1.5 inches) and write it down. Put a 100-200 miles on the chain and recheck the rollers and the slack. If the slack is out more than 1/2 inch from the original measurement replace the chain.

This takes a lot more time than just buying a new chain/sprocket set and installing it, but if you dont mind the time, it may be a cheaper way to keep a chain that isnt bad.