I'm in Peru right now and bike has been burning more than usual oil for last 3 weeks or so. It has 23k on it now and I use 20w-50. I've put oil to upper line on the window and about 200 miles later it was at lower line. I change oil and filter every 3-4k miles. Last time I changed it was in Venezuela and I'm still using some of their oil, Cark brand. Since that oil change bike was running great for next 2 months through Venezuela and Colombia and it seem like it was actually burning less than for previous 7 months on this trip through Central and South America. I've been riding more at higher altitude lately through Ecuador and Peru. Not sure if that might be reason? Should I switch to different viscosity? I stick mainly along the coast where it's pleasant summer temperature. Every 4-5 days I go up the mountains for few days where it's cooler (but not freezing cold) at about 3000-4000 meters altitude.