I have been toying around with the idea of a mechanic fuel injection system for my bike as well, thinking of ways that I could do it. Here is what my basic idea was, I'm sure that it could be adapted for an electrical though.
Components:
1. Throttle body
2. Two Fuel Nozzles with manifold
3. Fuel Metering Unit
4. Vacuum Driven Leaning Valve
5. Boost pump
6. Momentary switch
7. Oil Pressure switch
You have one throttle body which is just a machined block of aluminum with a throttle plate inside. So it has throttle linkage on one side, this is driven by your twist grip on the bike. On the other side of the throttle body you have a fuel metering valve which is a rotary valve. As you increase throttle position, the fuel metering valve is rotated allowing more fuel to be sent to the fuel nozzles. Now depending on throttle position the manifold pressure increases in the intake, a small line is tapped off the intake to a vacuum valve that will partially open and close to control the mixture depending on the amount of air is flowing through the intake.
It is temperature compensating because when Outside Air Temp is cold, the density is high, therefore more vacuum will be pulled on the valve which will lean the mixture out. The diaphragm also gets impact air on one side, and vacuum on the other. Depending on impact air will determine the action of the vacuum diaphragm. This way if there is less air rushing into the intake, the vacuum will pull more and fuel will flow to the nozzles. As impact air increases, we can lean the mixture out and impact air will close the diaphragm more to lean the mixture.
For starting, you press a small button which turns on a small boost pump and will shoot some prime right into the engine. Once running a oil pressure switch begins to run the pump. This acts as a engine safety switch - if engine runs out of oil, engine shuts down.
Sounds crazy but it is modeled after an aircraft so I don't see why it wouldn't work, I have changed it to work more for a motorcycle, including the boost pump and oil px switch. Thought I would share with you.