i have a 87 cbr 1000f
when i rode it had a dead spot from about 7 to 8 grand just flet like no power and then bam it wanted to go

i took the carbs off and cleaned then and got all the crud out of the bowls
now i have it all back together

now it starts fine and i let it warm up and the choke is off and i rev it up it goes to 6 grand and then falls back to about 2 then revs again to 6 and falls back to 2

but the bike idels fine

been threw the carbs 3 times and im just stuck

 

I'm old-school and always check the ignition advance with a timing light first. If it doesn't advance, replace the pulse generator. Then I would check the air filter. If you are sure the problem is in the carbs, the piston/needle inside each carb controls from just off idle to just below Wide Full Open. It's easy to test without taking the carbs off.

With the engine off and the airbox pulled away from the carbs, stick a finger in each carb throat, on the airbox side, and lift up the piston/needle. There should be slight air pressure resistance. When you let the piston drop, it should fall with a nice plastic "thunk". If the piston hangs up, drops slowly, or won't go up, you have to clean the piston and walls, by taking the tops off the carbs.

 

open the gas cap see if it does it ? check vac line to petcock as well

 

+1

 

checked the slides they all move free tryed it with the gas cap off still no change and the bike does not have a spot for a vac line on the petcock

and it was running before and i havent touched and of the timeing ajustments so all of that should be good

has all new pluggs and spark on all cylinders

 

Maybe a partially blocked fuel line from the tank. There's a filter in the petcock - may have crud in
it..........
ALSO, CHECK THE FUEL FLOW BY OPENING THE BOWL SCREWS TO CHECK FLOW, AND MAYBE BOWL NEEDLE AND SEATS IN THE FLOATS ARE STUCK.

 

all the bowls have fuel and i checked the floats and needel valves all that is good

no clogs in the lines
got the bike together and its quick till it hits 6000 rpm then falls on its face

 

6000RPM is where the power comes in.
Sounds like insufficient fuel flow..........

 

you think it could be the fuel pump or the fuel air mix??

 

Take the fuel pump out of the equation by taking it out of the line and see if the flow by gravity gives you a better result. If it does, there's your problem. Some owners remove them altogether but I believe the rice-burners wouldn't have fitted it if it wasn't necessary (especially when full power is required)
If you set the fuel/air mixtures at 2.5 turns out it should be fine. May run a little rich but rather that than too lean.