With the primary drive components removed, give the crankshaft a good in/out push and pull. There should be just a small amount of end float, most likely the crank will move with a bit of a distinct clunk. This float is controlled by circular shim washers between the main bearing inner race and the crank web. A loose primary retaining nut means the bearing inner race can move and this will wear away the shims (and the crank web, in bad examples).
Debris on the sump plate gauze is where it all ends up. These initial checks will give further insight in what to expect when the cases come apart.....don't forget the nut on the internal casting web above the camshaft. With all retaining nuts and studs removed, the casings come apart fairly easily, use a heat gun to soften any jointing, resist the temptation to lever the cases brutally apart, the sealing faces are narrow and easily damaged by cold chisels and other hooligan tricks.
Most of the standard parts are fine for your style of use. A roller bearing end fed crank mod is well documented, expensive, but not necessary for leisure riding. Sump plate with a drain, raising the overall gear ratio with different primary and gearbox sprockets and a filter in the oil return to the tank are simple mods which bring immediate benefits and peace of mind. Brakes need good linings and setting up properly. Triumph type 4 Spring Clutch, as you have, just needs attention to detail to work well, far superior to the earlier BSA 6 Spring. All clutches suffer from drag, at least when it clunks you know you are in gear. Snick into neutral before a standstill, most boxes won't come out of gear without a struggle..... Plenty more on the Forum to explore.
Swarfy.
