Is it bad to rev a motorcycle to almost red line in neutral while its warming up?

does this harm the engine in any way? we’re still working on getting this thing to stay on without choke and my friend came over and he was like maxing the thing out all the way!! i dont know enough to tell if it sounded good or bad, but it sounded maxed out and got hot. is that what the engine is made for or is that bad for it?