there is no "power gain" by doing this. Having a heavier flywheel, or rotor actually, just means that you will accelerate slower, your HP number will not change. BUT, once you get up too speed your engine has alot more inertia and that means it will give you a feeling up morre torque in high RPMs, and if you are low in the RPMs then clutching will be more effective because your engine has alot more inertia to move the wheels with. You will also het a smoother power delivery which is better for slippery ground. Having a light rotor will give you more acceleration, thats about it. I know it doesnt sound like much compared to having a heavyier rotor but its a pretty big advantage, and you wont be able to keep the engine as low in the RPMs because there is not enough intertia to keep the engine spinning. And if you are dealing with a bigger engine kickstarting will be harder too. Just dont take too much off, 8 oz sounds like way too much. 3 oz will make a huge difference, trust me