| jgriff, I don't understand your explanation / reasoning.
The return side is only dealing with unused fuel from the injectors, these are pumping fuel back under pressure and this is fed thru the pipework and connectors into the degasser, and then straight back into the tank & not to the pump.
It's doing this as there are only certain throttle openings and revs where just about all of the fuel supplied is used by the injectors, at points below this only one injector is firing but the system is seeing fuel at the same pressure as when at high revs, hence the return of fuel under pressure.
On single injector motors the same symptom occurs thru the rev range, check out the injection timing charts in the falloon books, or the moto one performance index.
I know that the degasser was fitted as Duc had big problems with tank pressurisation which starved the motor of fuel, even when a tank breather was fitted - I think it starved the motor of fuel as the back pressure was greater than the pump pressure - hence the degasser and also the 'non-reversion valve', the valve halted back pressure and allowed one way flow only and a motor not starved of fuel.
This is the only logical reason I can come up with for it being there on the works bikes, more fuel demand, bigger pressures, bigger heat soak etc...led to tank over pressure
cheers
Neil  |