How do you check the oil level on the 2002 BMW r1150r?

Just put the bike up on it's stand or use the kick stand with a shim under to get the bike near level.
Then use a flash light and look low on the left side of the engine and you'll
see a small round flush mounted glass the size of a nickle.
The oil should appear dark on the bottom half of that sight glass and if properly filled said level will cut right through the middle of the glass...if the dark line is below half then add oil!