Hi Stu b ,GB, dutch ,john and Trevinoz, re the plunger clutch memories of my first plunger are of a pretty good device which required next to no adjustment and gave no problems whilst I tried my best to break it as only a 16 yr old could but never did ,it was followed next by my first experience of a 6 spring unit (that was the only time I ever though about jacking in BSA's ), my disgust of which I have remarked here about quite often . It went in the bin and I've always used 4 spring units since ,as john says not without there own problems but I've never been left at the side of the road by which did happen frequently during my brief time using the 6 spring. Trev, I believe that your unit would work and work well due to your eneat perfectionism , I know I'd never be able to achieve that so I stick with what I know. Best of luck Stu.