Just picked up a CBR F4 that had seemingly been abandoned by the previous owner. I have restored it back to what seems like a decent shape.

I replaced the battery, R/R & Stator. Everything else works as it should.

My problem is, when you turn the bike on and flip the killswitch the Fuel pump starts working, and instantly floods the carbs out. You can see fuel leaking straight into the engine, and the engine won't even start/crank.

The Floats, needles & valve have no wear, varnish, or rust. The carbs have just received a service.

Is this a fuel pump problem, there is a small nipple on the bottom of the tank and a vacuum line hanging off of the bottom of the fuel pump. Could this contribute?

I have tried gravity feeding it, but it barely idles/runs like this.

If you don't connect any type of fuel, it will eventually start and run fine until the bowls go dry.

 

It should run/idle while being gravity fed as long as its enough pressure going into the carbs. I've had mine for about 1 yr and its being gravity fed but I'm thinking about picking up a fuel pump for it.