Stupid Question from a Streetbike Guy

Good question. I'd like to know too. Don't many 2 strokes have rev limiters?

You have to change your way of thinking.

There are two things that primarily determine the red line on a four stroke, piston speed and valve float. Two strokes don't turn nearly the rpm's of a four stroke and, we don't have valves, so a traditional red line that you are use to doesn't apply.

There is a practical red line for a two stroke however. When the ports do not have enough time to complete a combustion cycle you are at the power limit of the engine. The engine can exceed this limit in rpm, but power drops off dramatically. Some call this over rev. There is little to gain in this part of the powerband because of diminishing returns.

Redline (or optimum shift point) isn't necessarily something that you want to identify by sound alone. There's a seat of the pants feel when the engine power starts to drop off. By the time the valves are floating or the ports are overwhelmed you are WAY past the optimum shift point.

Might be a good idea to have an accelerometer installed in your butt!

I see dudes hold the throttle at WOT all of the time, especially at the start of a race. I'm more of a "rever" myself. A two-stroke will rev until it simply can't rev any more and stay there.

I haven't tried holding the throttle open for an extended period of time, but if you can get a hold of your neighbors bike...