Motobecane bottom bracket thread?
 

Does anyone know for sure if my 1975 Motobecane Grand Touring has 'French' or 'Swiss' bottom bracket thread. Or, to but it another way, does the fixed cup have RH or LH thread. I do not see anything (such as rings) on the fixed cup.

My 1977 and my wife's 1976 both have Swiss threads, meaning the fixed cup is a lefty. You need a headset wrench to grab the flats on the cup - it ain't much fun, but it can be done!

Oops, correct that, I meant to say a BB wrench. The one I use came from the Nashbar Big Tool Kit - works great. Otherwise, you can use a large pair of Channel Locks WITH GREAT CARE, but if you slip, you're gonna do some damage. I highly recommend a BB wrench.

Huh?

I thought the fixed cup was always right threaded. The adjustable cup is either right or left threaded.

Nope!