[Keef Sparrow]

I have read that it was a popular fix for fighter planes, they'd inject the water to prevent detonation

It was introduced on American and German combat aircraft later in WW2 to boost power by cooling the fuel/air mixture as it went into the engine.

[Semanticks]

I imagine water injected at x0,0000 ft is much cooler. Not sure how effective it would be on a bike at or near sea level, but I'm far from an engineer. Seems a bit like the principle behind N0S. Cool the combustion chamber, cram in more fuel, gain more power....

Question, as always, is does it work?

[Marcsen]

Water-meth Injektion is a old hat . The bmw m3 gts came with it from factory .
There are several companies doing aftermarket products,  most known is snow performance.