Works by injecting an oxidising agent, allowing the engine to burn more fuel and so produce more power. There are two main types, a wet kit and a dry one. Both store nitrous oxide (laughing gas) in liquid form in a high-pressure bottle ideally at around 900 psi. The wet kit works best with carbs and has two solenoids that deliver fuel and nitrous directly into the inlet tracts on the engine side of the carbs, through one fogger nozzle per cylinder. The system usually has an arming and a micro switch and is activated by pressing the horn button at full throttle.
The dry kit works well on fuel injected bikes and usually has two nitrous-only injectors fitted into the air box. An electronic control box richens up the fuel delivery using the bike's injectors and also detects throttle position. The system again runs through an arming switch and is activated by the horn button at full throttle. This kit also takes advantage of the bike's gear position switch and can be programmed to only activate in certain gears. With both types of kit power gains of 50-80 bhp can be expected, and your engine will require little or no modification at these levels. Progressive controllers can also be used to pulse the solenoids, smoothing the delivery, if you don't like all your extra power in one big hit! Cost around £1,000 fitted.