scott123007
Well-Known Member
I know all about over revving from downshifting, but that is not what he said he did, so it's not part of this conversation...Dallara said:Just a note, Scott...
A rev limiter won't help out at all in any sort of mechanical over-rev condition. Think downshifting into too low a gear at too high a speed. The wheel speed can drag the engine speed much higher than the redline, and indeed do damage just as though it was over-revved under power with no rev limiter.
Some of his symptoms (rough idle, more vibration not cured by normal servicing, no low-speed power, and particularly it getting hot quick) sound remarkably like his *just* hitting/tapping a valve on a piston and bending it just enough it won't seat... Most likely an intake valve in this instance.
I sincerely hope that's not what happened to the OP... But I've seen it, and several times over the years, particularly on customers' bikes who did very similar things as the OP.
Rev limiters will save the valvetrain while under throttle, but chopping the throttle while seriously up in the red range can cause mechanical over-rev conditions. Best thing to do if you get caught in the situation of the OP is to immediately pull the clutch in as you roll out of the throttle so the engine drops RPM as quickly as possible... Don't let the wheel speed drag the engine speed along above the redline.
Just FYI...
Dallara
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Your other point about chopping the throttle "while seriously up in the red range" causing mechanical over rev conditions, is just plain WRONG. No way, no how can that happen by chopping the throttle. LOL (what do you think a rev limiter is doing?)