Hello Andrew
I too have just bought a TS125 for ‘tinkering’ and i found the bars touch the tank. There are two stops cast as part of the bottom yoke which should hit a lug which is part of the frame and comes out of the headstock straight down just behind the lower headrace. I suspect this has been broken off on yours. Mine had worn badly so I have had to drill the aluminium castings and put a 3mm bolt through with the hex head forming the actual stop against the steel lug and thereby giving some clearance to the bars against the tank. I am afraid I can’t do a photo as I’m new on here and I can’t seem to insert photos into my posts!!
