There is slightly more to it, but that’s essentially all it takes. The piston in the second cylinder flies around at 15,000 rpm, moving air but nothing else. The result is horsepower in the mid-60s, with predictable and linear power. “A really fresh one might make 70,” Wallis admits, “so the power isn’t dominant, but the torque’s about the same as the V-4 400s are putting out too, low or mid-30s.” Perhaps the most compelling part of this modification? It’s all reversible. Silicone can be removed, valves replaced, intake and exhaust opened, fuel flow restored, and the GSX-R450 becomes a 600 again.