Chain loose at 3 o'clock, tight at 9 o'clock.
Search isn't working for me right now but I'm damn sure a lot of people have had this problem.
The thing gets pretty tight (like 1/8" of play) when the right crank is at 9, then loose enough to have like, almost 1" of play when its at 3... my regular lbs sales guy never heard of it, he said it was normal. The mechanic there said bring it in tom. in the morning and he'll see what he can do, took it to r&a and they've never heard of that problem, their only solution was chainring/bb replacement...