Hi there!
I have a cbr 600 f from 98. Have a lot of fun with it, drives super well. I can always start my engine without choke. It start super good without choke. With choke it seems to drown and it cuts out, so it doesn't rev higher with choke on. but without choke it starts and runs. Both with cold and warm engine. It runs fine and pulls well, no dips or hikkups.
when I'm standing still and I accelerate to 9000 rpm then some black smoke comes out of the exhaust. not with normal driving.

Consumption is between 1:14 and 1:17. I have yet to check the spark plugs, but apparently it is running too rich at idle. Air filter has been replaced. I did not see a dirty air filter or air filter housing. Anyone have an idea what it could be. Leaking float or float needle? There is no gasoline in the oil. Also do not know whether it is absolutely necessary to open everything because it starts and runs very well.

 

My first thought would be the choke cable is broken and the choke is on all the time. Starting without choke is almost unheard of.

 

thanks, but then he would have to idle higher in rpm and not run well right?

 

It sounds like you have had the bike for a while and it used to start with choke , but it doesn't now .Is that right? You yourself are pointing to a rich mixture so have to ask why . Bearing in mind that the mains and needle wont affect starting mixture , and I assume you haven't altered anything , it would make you think either idle mixture screws or some sort of fuel leak . You really need to remove plugs and see if they are all the same colour , it's a bit of a pain to get to them , tank off and pull the ram air out the way , the side panels of the lower fairings need to be removed to access the ram air fixing screws .

 

It's possible PO had increased jet-sizes and added fuel with mixture-screws.

Then choke's not needed to start and using choke just drowns engine in extra petrol.

Verify ALL jets are factory-sized by measuring them. Insert wires of different diameters until one doesn't fit. Then measure previous one. Compare to charts on what actual jet-size should be. Not uncommon for people to massively drill out jets in mistaken belief that this will increase power.

Actual opposite is true. Remember that '60s hot-rod saying?

 

something, something injection, something, something blown….