i have a 88 cbr 600, it was sitting for three months, i changed the gas, the plugs, the air filter, the oil, got the carbs synched, it will start and run fine for a little bit, and then it will die like i ran out of gas, i will then let it sit and it will start up fine. any help will be appreciated. thank you

 

Battery?

 

Does the battery crank it, or do you have to jump start it? Did it run okay before it was parked? I've seen bikes die when they get hot because the valves were too tight, but it's unlikely that it shuts it down completely on a 4 cyl. bike. I'd make sure it was put together properly as far as vacuum and fuel lines, and check that the choke isn't sticking on or something.

 

is the tank clean? like no rust and stuff? if there's crap in the tank, and the battery is ok, you could have stuff jamming the petcock, which will effectively stop the motor. worth a check.

 

Chances are you have a tank vent line clogged or kinked. After starting the bike you build up pressure in the tank and it will not let the fuel flow to the carbs. Check the tank vent hose or the small hole in the top of the tank under the gas cap to make sure it is not plugged or clogged.

 

Check the air in the tires,lol. I did the same thing with my 88 Hurricane 600 and when i had the tank off and put it back on i had pinched a fuel line vent hose or fuel line hose im not sure its been 9 yrs ago now, check them when laying the tank back down, hope this helps

 

Carb icing?

 

check the fuel pump and filter. mine did the same when i got it.
the pump was on the way out.[:@]

 

A low battery can cause the problem..has enough juice to start but the constant drain at idle causes voltage drop and stalling. The charging system doesnt put out much till 5000rpm. Charge it up it goes for a while is consistant with a weak battery. I replace my battery every two years.

 

Check back in after you check all of the above.
Some of the only things not listed here which i can think of would be idle adjustment...
Sounds like your starving it.
Does it still die when you give it revs or does it just die when idleing?
I will second the choke checking.

A way to check if it is your petcock is to loosen one or two of the bleed valves that are sitting right below your carbs. You shouldnt be able to miss them. They would probably still be facing out on an older model like yours right below the carb on the left hand side. If there is gas dripping from those after a couple turns its not your petcock or fuel filter or pump. The answer would have to lay in one of your other options.