I have a 2009 KLR 650, just past 70,700 miles. When I got the bike with 2000 miles on it the oil had be changed once at a dealer. Since then I had only run Rotella T 15-40 non-synthetic. I had the oil tested twice, 1st was a round 12,000, 2nd around 20,000. Both test showed what was considered normal wear metals, and the oil itself was withing acceptable shear levels at 5000 mile change intervals. so I haven't had it tested since. Compression is good, shifts good, clutch doesn't slip, and I still get better than 58 mpg average. I check the magnetic plug for metal at every oil change, so far, so good! I changed to Castrol 20w-50 last summer, the clutch acted different so I went back to Rotella.Maybe I should have the oil tested again?