When you accelarate at about 8000 rpm the bike stalls untill you let off the gas

Hi there
With the little info you have given here, I can give you the most probable thing that is affecting your bike. It is hard to diagnose these sorts of problems without actually looking at the machine. When the engine dies like the ignition has been turned off under throttle, and then lights up again when the throttle is rolled off, this is a sure sign that it is leaning out, in real terms "starving for fuel" when the power is on. This can be caused by many things, but mostly fuel filter clogged, main jets clogged, varnish buildup in the fuel system, particularly carbies/injectors or fuel petcock. You will need to give the entire fuel system a clean, easiest done initially using a good quality fuel system cleaner additive such as Nulon or Techron. This may easily resolve the problem for you, and is the easiest place to start. If not, then it may take a strip down and manual clean of these parts to bring back to life again. Be aware after using these sorts of products, you will need to do an oil change on the bike. Carbon deposits from the combustion chambers will make their way into the oil and best to drain and replace the oil after you have run a tank full with additive through the bike.
regards robotek

Greetings,
I believe your problem is fuel starvation, which might be caused by one of two things. I would first replace the fuel filter. Also, check your air filters to be sure they are clean, dry, and not contaminated. If you have the vacuum controlled fuel safety valve, check the hoses and all the connections. If all of the above is OK, drain some of the gas out of the tank at the petcock into a glass container and carefully examine the fuel for contaminants, especially for water and rust or other foreign materials.