5/8 x 3/8 is the size/pitch of the sprocket teeth, so - as you discovered - the overall widths of the chain can vary and still be intended to fit the same size sprocket.. The gap between those outer plates and inner plates looks like an 'O' or 'X' ring chain would look, standard chains would normally have the plates pretty much touching.. I can't vouch for BSA but most British bikes were made in an era when seal-type chains didn't exist, so no allowance was made for wider chains, I do know that on some bikes it isn't possible to fit chains with seals because they would chew the back of the Primary Chaincase and/or gearbox.. Also, drive chains can flail about a bit at speed, so keep a careful eye on it to make sure it doesn't eat something expensive !..
@@jjrider6758 Thanks for the comment as always 😊. I kind of stumbled across that chain when I was deliberating on the rather expensive RK X-ring options. Thought it was worth the risk at only £20 and I confirmed that it wasn’t an O or X-ring with the supplier, but it is quite wide as you can see. A few days after, I had my head under the bike near the centre stand and you can actually see the clearance to the engine, as you can from the back of the bike at a squint. Plenty of clearance for this one so I’m comfortable with it and I made a slight adjustment to the chain slack after my camping trip. So I think we’re all good👌🏼. Need to make sure it’s properly dried after each wash and lubricated as the rust on the old one was a bit of a surprise I must admit!
5/8 x 3/8 is the size/pitch of the sprocket teeth, so - as you discovered - the overall widths of the chain can vary and still be intended to fit the same size sprocket.. The gap between those outer plates and inner plates looks like an 'O' or 'X' ring chain would look, standard chains would normally have the plates pretty much touching.. I can't vouch for BSA but most British bikes were made in an era when seal-type chains didn't exist, so no allowance was made for wider chains, I do know that on some bikes it isn't possible to fit chains with seals because they would chew the back of the Primary Chaincase and/or gearbox.. Also, drive chains can flail about a bit at speed, so keep a careful eye on it to make sure it doesn't eat something expensive !..
@@jjrider6758 Thanks for the comment as always 😊. I kind of stumbled across that chain when I was deliberating on the rather expensive RK X-ring options. Thought it was worth the risk at only £20 and I confirmed that it wasn’t an O or X-ring with the supplier, but it is quite wide as you can see.
A few days after, I had my head under the bike near the centre stand and you can actually see the clearance to the engine, as you can from the back of the bike at a squint. Plenty of clearance for this one so I’m comfortable with it and I made a slight adjustment to the chain slack after my camping trip. So I think we’re all good👌🏼.
Need to make sure it’s properly dried after each wash and lubricated as the rust on the old one was a bit of a surprise I must admit!