Why do bikers rev the nuts off bikes to show displeasure ?

[nervous]

fergus said:

Most alternators don't start generating output until the engine is doing around 2k revs. Once the engine has done this once, the alternator will charge at idle. Some have an 'exciter' circuit to start the alternator generating current at lower revs.

The other old chestnut is when the bike perhaps isn't running properly. The cure? Rev the nuts off the bike when under no load in the pits - that will obviously lead the highly unskilled "mechanic" looking at the problem to the source of the issue

Whilst they lean, staring intensely over the dash. You mustn't forget that. The lean and the scrutiny is everything.