After a crash (happened few days ago), there seems to be no oil pressure in the engine (the oil pressure light stays on). The engine didn't damaged visibly, actually there are rollbars on each side, and nothing is damage close to the engine, and it starts instantly.
Last year when i was pulling the ER-5 out from the garage, i've stumbled on something, so fallen with the bike, and the oil light stayed on, which is as i heard normal for a half hour because air bubbles or something, but for me that problem existed even after a day, so i've drained the oil, pulled out the pressure switch cleaned and tested it(multimeter, and compressed air), i've put it back, fill back the oil, and everything was ok. So i did the same this time, but the oil light still stays on :(
When the engine runs there is some clapping, clicking noise, which is the most audible/loud from the right side.
What are the problems?