For many years I ran minis. I think I owned 5 in succession. I would buy them at about 3 years and keep them about 4. The mini clutch is well known to be a bit on the small side, particularly for the more powerful ones, so the first evening of decent weather after buying one, I would renew the clutch. The whole assembly is inside out, with the flywheel sitting on a taper outside the clutch, with a single big bolt through the middle. There is a special tool (a plate ring spanner, that does the flywheel bolt, the front suspension ball joints and the first motion shaft in the gearbox). You have to take the starter off anyway, to allow the application of a hammer to break the taper holding the flywheel on in conjunction with a threaded puller (a plate with 3 bolts in it), so a screwdriver in the ring gear prevents rotation. Simple. I could dash home from work at 16:00, (17 minutes walk), grab a bite to eat change a clutch and be in the pub (2 mins walk) before last orders at 22:50, even allowing handwashing time.

A tale about tops of pistons. Before I could afford a car, I ran around on a Honda 50 (C100, the early push rod model). Due to a muffed downward gear change when going down a steep hill in county Durham, I overreved it, whereupon it lost compression. Stripping revealed a bent valve, which was renewed & the whole lot thrown back together without a further thought. The valve had hit the top of the piston to achieve its modified shape. The valves on that engine are steeply inclined, and it had hit right at the edge of the piston. About 2000 miles later, it started smoking and drinking oil. Stripped it, top ring broken because it had jammed in its groove which had been tightened by the impact, so now it wanted a piston, rings and a rebore due to the consequent damage which could have all been avoided if I had pulled the barrel & checked the rings at the first repair. The upshot is: don't apply point loads to the tops of pistons on i/c engines. They are intended for even gas pressures. All I would ever put down the spark plug or injector hole of an i/c engine is a dial gauge for the purpose of determining TDC.

Eddie