Motorcycle Repair: Fix rusty chain, rear sprocket, shop towels

Question
Just got an '82 CB750K. It was in the rain for awhile and the chain is rusty but moves. What can I use on it to loosen/de-rust it?

Answer
Hi Mart, You know if that chain was to fail it would in all likely hood break the engine case. Then you would be kicking your self for not replacing it when you had it off the bike. I dont trust those rusty chains and master links. It could be an endless chain too, without a master link.  If I wasn't succesful in persuading you to buy a new chain and your determined to clean up the one you have...then a stiff brush, gallon kerosene, large can WD-40, large bundle of shop towels and an afternoon of your time. If it has a master link remove it and the chain from the bike. Alternate scrubbing it down with kerosene then WD-40,if it is an endless chain clean it on the bike, be sure to get the back side, underside and rear sprocket. Make sure you have fresh air. Once chains get rusty there forever going to look rusty so dont kill yourself trying to bring back that shiny chain lustre. When you reach a point thats satisfactory, check for binding spots. Now...there are only two things on this planet you should ever use to lube your chain..(and this is a hotly debated subject) One is: WD-40
It's clean, doesnt throw all over the place, inexpensive and you can buy it anywhere. Down side is: It requires frequent application..like every time you ride and carry a small can with you on longer rides. Two: Mobile One 80w90w Synthetic Gear Lube. This is the gods nectar for chains. Apply once or twice a month and no worries. Downside is: It throws all over the bike at first, it is spendy, not as easy to locate and the bottle always tips over and leaves a mess. Personaly? I alternate..80w90w..go out and ride..come home clean all the splooge off...then WD-40 for a month or so. Well thats it Mart..have fun be safe

     respectfully
               Randy