In 2016 I was asked to make a cap for CB450 tach drive. Well, I ended up making several, from 12x1.25 to 16x 1.25mm, 5 or 6 different sizes and thread pitches.. None of them fit. Finally found out early CB450's use a 12x1.00 thread for the tach cable. It's same size as a C50 from same era. With small diameter and fine thread it was kinda 'interesting' to machine recess for the internal o-ring. It sucked that I didn't find the 12x1.00 tap I had until yesterday, (had it for 25yrs or so) Only found it after I bought replacement.Here's a pic's, it's going in the mail tomorrow.