Compared with modern bikes, our gearboxes are a bit slow and notchy. Well, all my BSA and Norton boxes have been. Which is why when I recently rebuild my GF I installed a roller camplate plunger instead of the original cone shaped item. The difference is amazing - positively silky changes. I don't know if they are commercially available, because I made my own after seeing a picture of one online some while ago. Well worth changing, in my view. Photo of device attached.