. . . on a 100 mile ride the oil level will go from bang in the middle to not visible in the oil sight glass, 4 - 6 ounces.
BMW's listed permissible oil consumption is 0.15l per 100km which is 5fl. oz per 62 miles so, for my own understanding if for no other reason:
0.15l = 5fl. oz. 100km = 62miles ~160km = 100 miles
100 miles is 1.6 times greater distance than 100 kilometers
0.15l x 1.6 = 0.24l 0.24l = 8.1fl. oz
In conclusion:
BMW's
permissible oil consumption is a whopping 8fl oz per 100
miles. This could be a case of corporate CYA, it could just be the way things were at a past pinnacle of Teutonic engineering, or it could be I'm out to lunch again. Regardless, your moto's oil consumption by your own calculation is 4–6fl oz per 100 miles. It's well within spec if your measurement when adding oil has been accurate.
:yippee:
It doesn't seem to me yet that there is much wrong with your moto; one of its intake valves was out of spec 8 months ago. It's probably not the optimal design for tropical mountain riding, especially two-up but it can do it. It's smooth running and stable if you'll ride your own ride instead of trying to keep up with others, as you already mentioned. If compression testing (or exhaust gas testing) doesn't indicate a leaking head gasket or another form of impending doom, I'd say you're good to go after a valve adjustment and throttle body balance.
