They still make power as they rev past the power peak at 5800 rpm, but they make less and less power as they rev toward destruction. That might be a bit overly dramatic. I've revved mine past 5800 rpm a great many times without an issue. I think the manufacturer's warning " Do not exceed 7000 rpm" for the 850 is a good one to use.
For getting down the road fast, I now use 62-6300 as a shift point. That is after looking at a few dyno charts for stock 850s. Prior to that I used a higher rpm and thought that was the way to go. Assuming my 850 dyno chart is shaped like the one below, 62 -6300 is going to work better than 66 or 6700 , my old favourite shift point.
The 850 has so much midrange grunt that you really aren't missing much if you shift it at a lower point yet, say 5500 revs. It will be a little slower than with the 6300 rpm shift point but should last a little longer too.
What the rider thinks is happening regarding acceleration and what is actually happening are almost always two different things.
It's probably safe to say that all of the popular Commando high performance cams raise the peak power rpm somewhat. The charts I have looked at seem so show a power peak around 6300-6500 for the PW3 and similar.
A stock 850 dyno chart
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