I'm with Jethro "Mantra for the club Has Always been....For Those With An Interest In Four Stroke Singles !"
Anyway I always thought that to "thump" like an old Panther probably involved a heavy flywheel. If you wanted a quick reving engine, for instance in a racing bike, a lighter flywheel was needed. As usual I have probably got it all wrong and some one will come forward with their physics "O" level and talk about torque etc.
Having long since been an admirer of large heavyoil standing engines with large flywheels which only fired when the revs dropped below a set RPM, that is what I understand as an engine that Thumps, SWMBO says I cant have one though or a T20 fergy.