xs EFI conversion fuel system issues

I've got one of these pumps set up on my XS750 EFI conversion.

The pump draws in fuel from the tank via a 10mm hose (you want minimum resistance on the inlet to avoid a slight vacuum and vapor bubbles forming) to the 10mm inlet on the pump. The pump is constant flow (might reduce a little under load, but you get the idea) and I reckon it is about 0.5L/min. If anyone has any specs on the pump, please let us know as I couldn't find any.

Anyway the output from the pump is channelled by the regulator to the injectors via the 6mm outlet until the pressure reaches ~45psi and then remainder is returned to the tank. The return line should not have any significant pressure - maybe a couple of psi only. The tank should not be put under any pressure.

Hence only the injector outlet, feed and injectors see 45psi.

This does mean that at idle >95% of the pump output is being returned to the tank. At full power there should still be some return, as you never want to be in the situation that the injectors are trying to flow more than the pump output - the pressure would drop and the mixture would go lean.

The pump is used on several ATVs and the Honda 1300 cruiser - the latter puts out ~57 BHP. I reckon my XS750 is at ~70 BHP and I've not seen any pressure drop at full power.

Hope this helps, Jon.