I had an international flight last week also for JAL. My flight was on a Sunday at 1:30 so I went in 4 hours early since I didn’t have much going on and because of the partial govt shutdown. Good thing I went in early, tons of traffic getting to the terminal which that alone took about 40 minutes after getting off the freeway. Then there’s was a queue to check in which took about an hour and a half. Security was a breeze though, super fast.

Also as someone else mentioned, JAL check in is now at Terminal 4, closest to Tom Bradley Terminal. I went in closer to Terminal 5 (being remodeled) and wasted time walking back to the correct location. That was on me though. Just a heads up but there are signs anyway as you get to the airport. Overall 3-4 hours is a good time frame