My neighbor wants me to turn his girlfriends '71 Peugeot into a single speed. I have never worked on french bikes before and was wondering what it is I need to adapt the bottom bracket to a standard size so I can replace the crankset.
Is there a standard kit I can buy that will adapt from french threading and if so what is a good one?
I'm not use what you mean by "kit" exactly, but here's a French-threaded bottom bracket with a JIS spindle:
You'll just need to determine the appropriate width based on which particular cranks you plan to use.
Velo Orange sells French thread sealed bottom brackets. If it is running smooth there is no need to replace it. You might want to repack it with grease, or even replace the ball bearings. The more serious question is whether the rear hub has English or French threads for the freewheel.
The bb is actually fine but the crank chainrings need to be replaced and the crankset is cottered, so finding a replacement might be difficult; I wish I lived closer to West Town Bikes. I have a replacement I can use but I would need a square tapered bb instead of the current cottered version, hence a new bb that will properly fit. I will probably just order the one off Velo-Orange once I figure out the spindle length.