I wonder if you'd see signs of slipage on the barrel wall when you open it or on the grease there?
Another possibility is if you have received a new faulty, weak MS, especially that it feels smooth as you wind, If the old one is undamaged and you find it stronger than the new one, you have found the fault. Weak MS exerts weak force against the wall, therefore weaker force of friction developes there, hence weak power reserve.
I missed the initial section of your thread. When it stops, I give the barrel a nudge to see if it runs a lengthy second stage.
Motorcycle references tickles me too, as one needs to make them right . The Ducati Monster is just (like a watch model) name for their popular naked bike style. They come as small as 400c with power adequate for a beginner and the related license. Monster was ever meant to deliver big power, not even in it's 1200cc declination, or track use. 20 years ago the overused reference for a top performance bike was perhaps an Hayabusa, more modernly maybe Ducati V4, or a Ninja H2R.