Reading this thread makes me more and more happy to have moved away from clone motors. LOL But seriously, I didn't move away because of rules but it is fun to keep up with them while not having to worry about complying. I've always felt that with a base component that is produced by multiple Chinese manufacturers to varying standards it is nothing but an uphill battle to contain racers (and builders) always looking for an edge. I do agree that trying to limit the clone with valve springs is lunacy. If I were the rule czar, and it's probably a very good thing I'm not, I would make it as simple as possible.
#1 rule, safety first. Billet flywheels required, billet rods optional, remote mounted fuel tanks, etc.
Rule #2 Displacement. Whether it's by bore & stroke or some other method doesn't really matter, just limit the motor size to <200 CC
Rule #3 CC rule as it currently stands.
Rule #4 Weenie pipe exhaust to current rules (personally I hated the weenie pipe but it is a great restrictor and caused fewer burns on my arm).
Rule #5 Restrict the carburetor, preferably with a restrictor plate.
Rule #6 Maximum jet size
Rule #7 Pump gas at 87 octane maximum (our track specifies where it has to be purchased and compares)
If a motor can't breathe on either end and you can't squeeze it real tight in the combustion chamber the power and RPM are limited by the laws of physics. You can port & polish, play with springs, high dollar pistons, etc to your hearts content but the gains if any are going to be nil to negligible at best. Now I realize you clone racers feel like .001 HP makes or breaks you in a race but really?
Tech becomes a quick and simple process requiring minimal tools and talent. Anyone could tech their own motors in 10 minutes.
You could even go one step further with sealed carburetors from approved builders if you wanted to.
Or sealed motors
I know, I brought this up on the old forum and sealed motors won't work for clones, only for just about every other form of motorsports. Clones are special.