The fact is that many, many engines are driven over their limit for short bursts. If this were not the case everyone who ever missed a shift or loaned their ride out to an inexperienced friend would be replacing cranks. Even during the Algodones to Glamis via TRX article I wrote some time ago I expressed driving the quad for sustained periods at well over 9300 RPM - I had that throttle held wide open for fifteen miles (Ted Kife Rd.). And I don't mean revving high for fifteen miles under no load, I actually had the throttle turned as far as it would go for the entire duration of that boring strip. That's what a Honda crank can withstand. How many feet was that?
I use the 4000 ft per minute as a good starting point, but in the world of racing it's just that - a starting point. The venerable Honda's are capable of revs well beyond that - especially on TT tracks and other types of racing that require overrev. It seems these days there is more of a danger of a crank coming out of phase than a piston breaking or sticking due to overrev, and even then with the quality of bearings made now the envelope has been pushed much further. The 4000 ft rule is a good one and matters a lot, but like all rules they're there to be tested. In some cases it really matters.
Please know that I do not recommend others to do the stupid things I do on my TRX. If you twist yours up to ten grand and it spits the piston out the exhaust port please don't send me hate mail. Remember the end of that story. When I looked at the bike in the morning the frame was broken in several places. Some of that was most likely due to running at the elevated rev level for such a great distance. But, trade that experience for anything? No way. I'll keep that one because it was an absolutely wonderful ride that will never be duplicated. In fact, just thinking about it makes me want to make the run again...
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