Aaaargh - (forgive the pun!) - that has led to a fettling chain reaction which shows no sign of abating!It turns out with the worn chain I can just get it to work with the wheel axle at the front of the dropouts. I could really do with putting a half-link in the chain to be able to move the wheel back a bit, but I think I will get away with it for now. I'll buy a half-link soon.
It is nice and quiet with the chain going directly round the ring and sprocket, and no tensioner/derailleur involved. I may eventually decide to use the ss Basso on the road, and the Specialized (with its slightly noisy chain tensioner) on the turbo. I can sort that out later.
The chain on the Basso s-s turns out to be badly worn and the sprocket on the bike is badly worn too. I have a replacement sprocket handy and want to put that on before replacing the chain. The rear wheel is one that I took off the Specialized s-s because the freehub needs servicing and the sprocket is worn! The reason I didn't replace the sprocket and service the freehub then was because I had ridiculously overtightened the lockring and broke my chainwhip trying to undo it!
I repaired the chainwhip and promptly broke it again... Now I need to re-repair it before trying what I had intended to do in the first place which is to pour boiling water onto the lockring before trying to undo it. I think that thermal expansion may loosen it enough to get it undone.
Once I have managed to do this I will put a lightly worn chain on, taken from my best bike, and put a new chain on that.
I also discovered that the chain on the Specialized is worn, and found another lightly worn chain that I can replace that with.
I don't like the handlebar on the Basso so that will have to go too. I have a vague memory of there being a spare one in a box in my cellar somewhere so I will go down there to hunt for it once I have sorted out the chainwhip/sprocket/hub/chain problems!
After that I will sort the other chains out and clean all 3 bikes.