I'm fitting a new rear chain to my WM20. The old chain has 93 links & lived there quite happily. 2 of my BSA books say to use 95. With 95 I've passed the limit of the adjusting cam & I could probably pull the wheel backward out of its slots. The sprockets are standard.
Does anyone know something about this?
I think it must be the primary chain. The motor went into the bike in the mid 1990s as an unsuccessful attempt at a 730cc or so motor with a large engine sprocket. Perhaps the current chain has been predicated on the longer one required for the large sprocket, I can't remember off hand. The gearbox retaining bolts are further to the front than the rear in their slots, the gearbox isn't in an extreme position.