bought a 99 cbr f4 carburated. and it floods the carbs. I took it to the dealer and they said the problem was the carbs and they would rebuild them for 500.00 I thought that was high and I have some mech. experence so I took it home and did it myself. it didnt help at all. I started with out air box and could hear that the carbs were being pressureized I removed the 2 hoses from the top of the carbs that tee then go to the valve cover and it stops it from flooding. I did change the oil because the fuel had flooded the crank case. I was wondering somebody could help me with this crankcase pressure problem as the bike does run but not real well with those hoses off.

 

How did you clean the carbs? And did you blow out the passages with carb cleaner and compressed air? Did you do a parts cleaner dip/PineSol dip?

I don't know why the crankcase pressure would flood your carbs. Maybe someone will chime in.

 

the carbs are fine it doesnt flood with those hoses removed . I found that if i ran it by bypassing the fuel pump and gravity feeding fuel that there was so much pressure in the carbs it would blow the gas back out of hose I used to feed the carbs

 

Does anybody know if there is a pressure relief valve on these or what the problem could be?

 

pull the float pin out and remove the float needle. You could clean it/check it, but the seats might be bad, check float height too. Make sure it is in spec. I don't think those hoses are your problem. They could be, I don't know enough about how the crank pressure is used but whenever carbs flood, the first place to look is the float height and float needles.

 

I checked the floats they all are fine the carbs do not flood if those hoses are removed if it was the floats would'nt it do it even with those hoses off? if I start the bike with those hoses on then shut it off I can hear the pressure leaking out of the carbs for about 5 seconds after the motor has stopped?

 

Not sure what hoses you are talking about. air hoses,water hoses, there are a couple different ones on the F4. You could check the manual to be sure that all the hoses are hooked up properly, and if they are, be sure all of them are clean and flowing properly.

Again, I don't know enough about the F4 to put you in a better direction than that.

 

two small hoses that come off of the top of the carbs near the vac. chambers go to a tee then a larger hose comes off of the tee to the valve cover. on the carbs its kinda like a rail that connects all 4 carbs into those 2 hoses. I hope this helps. i was googling cbr crankcase pressure and it appears like these bikes maybe had issues with this? being that it is a 99 taking it to the dealer is too expensive. but I would like to ride it this summer

 

I am going to do a compression test today maybe that will tell me something I will post results

 

I guess a compression test never hurts but I think your problem lies in the carb/fuel system. Repost this in the F4 section, and while you are at it, if you dont have a manual, get this (Downloads :: Honda CBR600F4 Repair Manual) and check section 5. There are a lot of things on the F4 that I am not savvy with that I noticed in that section. You could check the air vent control solenoid and the fuel relay.