I have a 67 Suzuki K10 that I fixed up. Found it on CL it sat for over 30 years. Initially, I gunk soaked the crankcase to free up the crank and cleaned up the top end and replaced all of the seals. It ran fine until it locked up. The crank had locked up and after it cooled down it ran but I could hear the right crank bearing sounding like loose marbles.
I tore it down and had the crank trued, replaced all bearings and seals again, and rebored it.
The right side of the crank has two bearings with a notched spacer between them. The notches line up with a hole in the case that is within the transfer port. The inner bearing is spaced out .5mm from the crank by the shim between, so it doesnt get alot of premix flow through it and out into the outer bearing. Premix flow diagram from the 60s show the mix going through the inner bearing, spacer, them dead ending at the outer bearing and then travelling up the hole through the transfer port on the compression stroke.
It runs fine but after it heats up and runs over 40 mph for a stretch, the outer bearing gets loud. I was thinking that if I chamfered the oil passage hole in the case transfer port, tbe oil might flow better to the outer bearing.
This problem was fixed in the next prod year by adding oil inject, the pump was located on the right end of the crank snd oil was pumped tight into thebearings.
Has anyone had a K10, or can recommend mods to improve lubrication of the right bearings? I am using conventional Valvoline 2 stroke motorcycle oil, 32:1. Stock setup. Runs lousy with more oil. (edited)