If you want the clone class to realllllly take off? Make everyone buy a Burris(tm) type subplate motor mount, then the track / club buys a pallet of clones. An adapter plate and throttle cable get bolted on each engine. Then at sign in you draw for qualifying position and you draw your motor number. You go the the engine shed an pick up your clone with 3/4" shoe clutch. Run 'em box stock with tank and box muffler, only overriding the governor spring with a piece of wire. A good oil is run for the whole raceday. *Don't tell me it can't be done because we ran Tecumseh H35's with the same Kendall 10W30 for 4 complete racedays with no governor on asphalt with no appreciable wear.) At end of day, engine and clutch are turned back in. During the week or early on raceday oil gets changed and clutches verified for good function. Repeat process.
Both engine and clutch are maintained by the track and the resultant fees are integrated into the class entry fee. Some will be dogs, some will be fast, most will be in the middle, but the luck of the draw evens it out for the most part. A reasonable gear ratio limit is set, upper and lower, and spot-checked at weigh-in --- the clutches are all same tooth, and marked with a stamp, so it's easy to police ratio. A bit of extra work? Yes. As fair as you'll get? Yes. Low-hassle for the family -- yes.
At the extreme, you'd have parc ferme for tires too, but lets not get too tricky.....
Otherwise, if you want something to apply to today's clones, I'd spec a spring rate with open springs, I'd spec a billet flywheel and billet rod, and I'd spec a overall cc and valve size. Then the rest would be open. The can of worms was opened once y'all started changing them from as-shipped. And since you can't re-pack the worms, you might as well hurry up the rules creep until we've reached flathead-rules-equivalency. Then lock the rules down for 5 years, IMO. Stability breeds stability.....As far as I'm concerned, you could permanently lock the specs and then just let the builders and tinkerers play within the margins.
But I'm a UAS 2-cycle racer now, so what do I know?!
