To answer your question, the right side cam bearings are at the end of the oil circuit, low oil or restricted oil cause the problem.
Make sure to tear down the right side cover, check the oil pump for scoring and clean out the screen. Screen clean out is one of those normal KLR things that should be done within the first 1,000 miles or so, many don't believe and won't do it, we've seen them here fully plugged with junk.
Be sure the safest rule is that we should not dare to live in any scene in which we dare not die. ~Lewis Carroll~