One of the thing about restoring an older project bike is the fact that the carbys are 30 odd years old. Having spent most of my career in the automotive trade focused on Electronic Fuel Injection it was almost a certainty with my background that an EFI bike was going to happen.
In the last 25 years I have been involved in over 45 EFI conversions on cars, some as a complete project, and some just doing the electrical wiring.
My ‘Pumba’ XJ750 project is only months away from going over the pits and will be on the road for the end of winter. The engine in Pumba is unknown both in condition and mileage but is fine for getting the bike over the pits.
My spare engine has a known history and is low klms. I have ordered a full gasket set and it will be getting a full strip down and rebuild. This engine will be EFI.
1983 air cooled XJ750 EFI conversion.
Lets start basic and get complicated later.
An EFI conversion requires consideration of the following points;
Removal of carbs (DUH)
Some method of throttle (throttle bodies, one per cylinder on a bike)
High pressure fuel supply (30psi upwards)
High flow fuel supply return (more on this later)
ECU (Electronic Control Unit) to control things that needs the following inputs;
Engine speed and position (crank angle sensor)
Throttle position sensor
Engine temp sensor
Air temp sensor
Engine load (air flow or manifold pressure sensor)
So the start of the project is to do research on what parts to use and integrate into the system.