Need advice weather or not to run a fuel pump

[morfitt]

Hi guys and girls

I have a 1999 zx6r and i think the fuel pump has shat it self. There is power getting to it so that tells me the relay is working, put nothing is happening with the pump. I have taken the pump out and run the fuel straight from the tank to the carbie as previous bikes I've had don't run a fuel pump. It sems to run fine with out the pump. So should I get a new pump or just run it without 1. Any advice would be great. I know it's probably got a pump for reason which is why I'm asking this question.

[robracer]

A pump from the wreckers is a cheap fix, if it is the pump that is broken. there are many models that run the same pump so finding one should not be a problem.

[Slow and wobbly]

There are also generic pumps available that run between 2-6 psi. While it may run fine as is in light duties you may find that additional throttle indulgence will leave it lacking. It is possible that even on a straightforward continuous 100kmh run will see it foundering as the gravity feed is too slow to keep up with the engine demand.

[jl4049]

Not only that but at any speed the gravity feed from the fuel tank will not be able to push fuel into the float bowls as they are pressurized by the Ram air system.

[Slow and wobbly]

Not only that but at any speed the gravity feed from the fuel tank will not be able to push fuel into the float bowls as they are pressurized by the Ram air system.

Ram air will not affect fuel or the float bowls. Ram air is a force feeding of air to the air box only.

[bonester]

The little hose in the centre of the ram air duct pressurises the float bowls- at least on ZZR1100/1200.

[Slow and wobbly]

Sorry I'll rephrase. The float bowls are pressurised but only to equal the intake pressure thus balancing each other out. In essecnce if the ram air was working as intended then this would have no bearing on float level and fuel delivery.

Back to the begining though. Put a fuel pump in it.

[jl4049]

Ahh yes it does, You said it yourself mate, the equalising tube equalises the pressure in the float bowls and the airbox. As your speed increases and the pressure in the airbox rises, it will overcome the head pressure from the fuel in the tank and dramatically slow the bowl fill, or if going fast enough, stop it completely. You are right about it not affecting float height, but for it to truly balance out and have no affect, the tank would need to be pressurized as well, at the same rate as the airbox and floatbowls.

[Slow and wobbly]

Yep your right thanks for the enlightenment.

[jl4049]

I should have explained it better in my first post