Right, the kickstarter turns the tranny mainshaft. If the clutch is engaged, the tranny mainshaft turns the primary drive, which turns the crankshaft.
The idler pinion (on which the dwell cam is mounted) is gear-driven off the crankshaft, so it must turn if the crankshaft turns.
If you're feeling some resistance in the kicker, then it's likely that all the parts are there and the clutch is slipping. It could be as simple as an adjustment. It's been a long time since I've looked at a Norton
clutch, but I assume it has a pushrod clearance adjuster in the center of the pressure plate. Go there and back off that adjuster to where you know the pushrod is not in contact with the pressure plate, and see if the clutch still slips. If it still slips, then it's time to open the primary and see what's going on.