Pay attention. Important stuff was already relayed to you but you missed it because you don't see what is coming up.
#1...Buy only the good tool. It is strong enough for this job. It is called a triple square. A cheaper tool will sometimes break. Get the triple square socket from either Northwoods or Cycle Works. Both addresses are already in this thread. Do not try to remove the rod bolts with a socket that seems to fit "close enough". The proper tool fits. An improper fitted tool may ruin the rod bolt and it will then have to be cut out with a torch which will ruin the crank.
#2...It is a rod big end bearing. Do learn the proper name for stuff because it will save money and time in the future. A main bearing is also on the crankshaft. It is what holds the crank in the engine block. The main bearings are important but they are not the same as the rod bearings. So far you suspect a problem with a rod bearing. The rods also have a small end bearing. It's where the wrist pin or gudgeon pin is.
The rod bearings are easy to replace. They don't even cost a lot of money. But when they go bad there is a chance of problems with the crankshaft. It is the crankshaft that is the most concern at the moment. Get the piston off and the rod off the crank and you will be able to see the crank journal. Try to take a picture of the crank journal.
Do not throw any parts away. You may need these rod bolts for temporary assembly but they will not be used in final assembly. You should mark them somehow, a dab of paint works well but you could also cut a small notch in the heads with a file. Entire engines have been ruined because somebody reused the rod bolts. Don't make this mistake.
I know that there seems to be too much extraneous information sometimes. You will have to figure out what parts are real. You are in the big league with this level of engine repair.