It's an acronym for 'Kawasaki Integrated Powervalve System'.
The cover that says 'KIPS' doesn't access anything. There are no gears, levers, drums, flappers or other wonkerdoos under that cover.
It covers the Helmholtz Resonator (by name)..which amounts to nothing but space. Named for Herman L. F. von Helmholtz (1821-1894). You math whizzes can check his theory
HERE. ;)
A 2-smoke runs on a tuned exhaust system, it is important that it not leak anywhere.
The resonator cover needs to be intact.
From Eric Gorr's book "Motocross and Off-Road Performance Handbook", the resonator is used:
..to allow for dissipation of the compression wave that travels back up the exhaust pipe at low to mid rpm. Its important that the two valve covers (on a kx250) on the cylinder be sealed with gaskets...
THAT from:
HERE.
He can indeed just unbolt the cover and bolt on a new one. Make sure it is sealed as noted above.
BTW, there ARE access covers for the purpose of disassembly/maintenance of the KIPS. One on the left side, one on the right, one even in the middle!
...but they don't say 'KIPS' on 'em.