Cold Engine Rev

[TargetofGravity]

Recently purchased a Yamaha FZ8, have about 2200 miles on it before I had to put it away because of a surgery. All aside I had a friend who had come over and wanted to see it. We started it up and he ends up reving it a few times between 4k-6k and then once to 11k-12k before then shutting it off. Had to shake me head because its probably one of the worst things you can do to your bike, reving it cold and then shutting it down before it reaches operating temp. My question I guess is what are thoughts on any damage that might have been done? Any advice would be appreciated.

[Wrider]

Just once I wouldn't worry about it. I do know a guy who insists he's a mechanic, but revs the crap out of his vehicles until they're at operating temperatures. His 954, his Lightning (Ford truck), and several hoopties of his are all in need of/recently had the rings replaced and he can't figure out why. We've told him but he insists he's doing it correctly.

[fzrbiker]

Hmm if its done just once I think its ok, but if you do it regularly you can damage the valves and pistons.