As a matter of interest, took a peek at my '74 TX650A.
Red is AC probe from one of the 3 white stator wires. Blue is AC probe from the power bus at fuse box (only shows the variance around the 13.5v DC it was idling at).
Red shows stator events and blue shows the ignition events (including dwell time when voltage starts sinking):
Can see time markers are set at ignition intervals and show 58.61ms. 1000/58.61*60 = 1024 RPM. Powerbus voltage variance is 0.21v without any noticeable spikes. That variance from ignition events is pretty normal from my experience fooling around with automotive stuff, but normally I see more erratic spikes. Based on all the talk about how noisy these bikes are, I was a bit surprised it was this clean.
Anything can make it ugly, mostly bad grounds. My wiring is all new, new brushes, VR1010 regulator, new solid state rectifier, original stock rotor/stator, Pamco ignition.
IMO, it's not really worthwhile adding components to try to clean up the power. KISS. Just make sure your wiring is proper. Good clean solid grounds, hub/spoke power distribution, and good clean solid grounds. <- intentional redundancy lol. If you add an electrical component to the bike, most well made stuff will already have the circuitry to clean up what it needs. It's just not hard or expensive for a manufactured product. But when fooling around with homemade circuitry, a buck regulator is a great way to clean up power, and a simple RC filter for signal conditioning, but don't guess at it because the capacitors create delays which may or may not impact the timing of the signal you are conditioning.
I'm not a pro, just fooled around a lot with Megasquirt projects about 15 years ago. A true rabbit hole. Few arduino projects too. Hobby scope is a great thing to have. Also have a DC current clamp to plug into it which has been useful to see on a scope.