Loco is on track.
Another consideration: some motors, ok a lot of motors under 500 CC's hit better numbers on the dyno with the small bore pipes but once it's in the dunes and being hot lapped it gets so heat soaked that the bike is actually down quite substantially in power from bottom to top. So that particular motor might be better with small bore pipes for single drag races but be better off with a big bore if it is in the dunes, fields, open trails.