Bike bogging/slowing at rev limiter

[Gnasher]

Surely if it's losing power when it hits the rev limiter, it is doing what it's supposed to do. You're way past peak power by the time you get to those revs anyway and all you're doing is risking potentially catastrophic damage to the engine.

Yes, correct to a point, they are limited to stop them destroying themselves so taking it to the rev limiter won't cause any damage.  In fact part of tuning (race) is to move the rev limiter on occasion.

 
  I have never felt the need to redline mine, never mind bounce it off the rev limiter but I assume the ECU cuts the spark so if the carbs are still chucking fuel into the engine, wouldn't that mean unburnt fuel in the exhaust when the spark starts again maybe that could explain the popping. Just a thought, I'm no expert.

The rev limiter is way over the red line, so yes you're correct it's a waste of time in road tune.  The bike doesn't have an ECU as such, it has a basic set of engine ignition maps, which is what the TPS is all about.