Hello everyone, I知 trying to diagnose my 1998 Honda CBR600F3. The bike starts for a few seconds and then shuts off, and sometimes when it does run it blows black smoke, but most of the time it just cranks (and sounds normal while cranking). Fuel is visibly dripping into the airbox from one side in large amounts, and I can also hear fuel moving when I turn the key or try to start it. The carbs were checked and look clean visually, and it will run briefly on starter fluid before dying again. The bike sat for about a year before this started happening, though I知 not sure of its exact condition before that. I知 trying to figure out if this is a carb float/needle issue, vacuum issue, or something else common on this model before I tear deeper into it. I致e used ChatGPT to help narrow things down, but I want real mechanical input. I also have a picture of the airbox leak if that helps.

 

It is definitely a carb issue. If the bike has been sitting as stated, don't waste your time trying to pinpoint a specific thing to fix. When you fix that, another will be revealed.
Time and effort are better spent just completely going through them. A visual inspection doesn't provide much, as there are so many tiny fuel passageways you can't get to with the carb rack still on the bike.

 

Do you think a clean or rebuild will be needed

 

There is no way of knowing until you break them down.
The jets are brass. They can usually be cleaned given enough time and patience.
The old are another story. I am almost positive they would need to be replaced.
One other thing, since you are not the original owner, there痴 no way of knowing there is no way of knowing if all the parts are are correct or not. In these cases, I always assume they are incorrect until i prove they are the right ones.
People do some pretty janky things.

 

Ok thank you I知 going to try to take the carb off today just to see what I知 dealing with

 

You are very welcome. You're going to need a really long philips screwdriver. If there's a Harbor Freight near you, they sell a 22" set of both straight slot and philips.
That's what I use.