Hi guys, I have a 2000 honda cbr 600F4 with 30k miles on it. I downed my bike going around a corner too fast a few months ago and after that I started having all these problems.
Here the problems Im having, the bike starts and runs great, but after riding it for about 30 minutes it starts too lose power. As soon as i down shift all power is cut off and the speedo/tachometer drops to 0 with oil pressure lights on. It usually starts back up after 15 minutes or using the choke to start it up.

Here are some of the parts i've replaced:
new spark plugs
fuel filter
fuel pump
new battery
new oil/filter
new air filter
stator
regulator rectifier

 

I'm new to this bike but have you checked you're oil pressure? There is info in the manual on how to perform the test.