I’m in the process of building my first kart. I’m running a box predator with 10.8lb valve springs and I don’t have a clue on what clutch and why. I don’t understand the difference in 4 springs vs 6 springs, 2 disc vs 1 disc. Price difference seems to be several hundred dollars. I’ve read that optimal rpm is around 4800-5100 in racing trim. any insight would be appreciated.