It's not exactly an owners manual and there is a subsciption charge, but this may be useful:
Kawasaki EX250 Ninja 250 Online Service Manual : Cyclepedia Press LLC
also,
2009 Kawasaki Ninja 250R with a rundown on specs.
Excerpt:
Liquid Cooling
- Latest generation Denso radiator offers superior cooling with minimal space and weight
- Ring-fan uses a quiet-running motor that also saves space- Fins on the lower side of the crankcase further helps cool the engine.