05-05-15, 02:38 PM
Yamaha won't have bothered with the expense of a fuel pump if it runs fine without it. It might run fine on a full tank but when getting low on fuel the back of the tank is not much higher than the carbs so you might not get enough fuel for higher speeds or loads, particularly with the fuel filter which will also drop what little pressure there is when the tank is nearly empty.
You could run without a fuel filter that that could bring its own problems.
A side effect of removing the pump is that the fuel will be "on" 24/7/365. The fuel pump also acts as petrol tap that turns off when the ignition is off. Before petrol pumps bacame common on bikes you always had a petrol tap, usually vacuum operated from engine on bigger bikes so the petrol was only on when the engine was running or manually operated on smaller bikes or in a very few cases a solenoid operated tap was fitted.
You run the risk of draining the contents of your petrol tank through the carb overflow pipes if a small bit of dirt gets stuck in a float valve
You could run without a fuel filter that that could bring its own problems.
A side effect of removing the pump is that the fuel will be "on" 24/7/365. The fuel pump also acts as petrol tap that turns off when the ignition is off. Before petrol pumps bacame common on bikes you always had a petrol tap, usually vacuum operated from engine on bigger bikes so the petrol was only on when the engine was running or manually operated on smaller bikes or in a very few cases a solenoid operated tap was fitted.
You run the risk of draining the contents of your petrol tank through the carb overflow pipes if a small bit of dirt gets stuck in a float valve