The grooved half goes in the block. The ungrooved half goes in the cap.
The tang on the bearing has to fit into the block and cap.
The flat spots on a crank are called journals. There are main caps with bearings both sides that hold the crank in the block. The conn rods have similar bearings & they also attach to crank journals. The bearings are c-shaped copper things that go in the conn rod & main caps for the crank.
Bad crank bearings . If the crank bearings are bad when the car warms up it will loose oil pressure. The reason being is there are holes in the crank where the bearings are and if the bearings have too much space between the the car will never build up enough pressure the oil will just run past the bearings and run back into the pan
It's the place on the crank where the bearings ride.
Check for proper bearing clearance. It is easy to get the wrong size bearings.
yes
crank bearings are in need of replacement
yes
No.
In most engines, yes only if the crank is not damaged and measures correctly.
if your quad runs out of oil 1 of 2 things will happen. the crank bearings will over heat and shred apart and that will cause your piston not to rotate around the crank like its suppose to and it will beat up your cylinder walls pretty bad. the other thing is if the crank bearings don't go first the piston could get the cylinder walls hot and fuse itself into the cylinder. i had the tube that oil flows from the reservoir into the case break and it shredded my bearings. $700 worth of parts.
u can grease and change them so that should answer your question
On the main bearings, you should fall between .001, and .003. If it is high performance, and you are going to rev it, go .002. Looser will rev.