I hardly ever even look at the tach on my SM. It's mounted exactly where you would place it on your BA, and it's too small and out of your direct line of site to be worthwhile as a tool for riding. I pretty much shift by ear and it does me just fine. IMHO, the SM/BA tach is 'cute' but essentially just superfluous. I wish Triumph would have mounted a tach on our bikes that was up next to the speedo like it should be and like it is on the Bonnie.
You might try the BA.com classified section or eBaymotors for one.
