34751-ZY6-000 Honda SUSPENSION, ECU UNIT (Honda Code 7635048).

Fuel System Bleeding Procedure
When any type of service work is to be performed on the fuel system, move the machine to a safe and clean work area. Be sure there are no active smoking materials in the area. Do not let fuel get on a hot engine or electrical components. Do not let fuel spray on the skin or in the eyes.
No attempt should be made to start the engine until the fuel injection pump has been filled with fuel and air removed from the system, or serious damage can be caused to the fuel injection pump.
Hand priming is also a function of the fuel transfer pump. The hand primer is used to fill the fuel system and filters and to bleed air from the fuel system. Bleed after filters are serviced, fuel lines have been disconnected, or after running out of fuel. Check valves in the primer body prevent fuel from draining out of the system when engine is not running. 1. Loosen bleed screw (1) at the fuel filters. 2. Operate priming lever (2) on the fuel transfer pump until fuel flows freely with no air bubbles around the screw. Tighten the bleed screw. If the cam lobe on the camshaft that drives the fuel transfer pump is on maximum lift, priming lever (2) will not work. Turn the engine until priming lever (2) can be operated. 3. Disconnect the wire from the cold start heater. Turn the ignition switch ON.
If the cold start heater is turned on with fuel, with air, or no fuel supply at all, the unit will become distorted and have to be replaced. Also, fuel that is not burned can enter the combustion chamber and will cause hard starting, black exhaust smoke and engine noise. It can also cause hydraulic lockup.
4. Loosen fuel inlet fitting (3) at the fuel injection pump. Operate priming lever (2) until fuel flows freely with no air bubbles around the fitting. Tighten the fitting.5. Loosen hydraulic head vent screw (5) and governor vent screw (4). Operate priming lever (2) until fuel flows freely with no air bubbles around the screws. Tighten the governor vent screw first and then the hydraulic head vent screw. 6. Turn the ignition switch to OFF. Loosen fuel line nut (6) at the cold start heater. Operate priming lever (2) until fuel flows freely, with no air bubbles around the nut. Tighten the fuel line nut. 7. Connect the wire to the cold start heater. Loosen nuts (7) at nozzle ends of two fuel injection lines.8. Set the governor at the full open position and make sure the shutoff key is in the START position.9. Turn the engine with the starting motor until fuel, free from air bubbles, flows from both nuts (7) of the fuel injection lines.10. Tighten nuts (7) of the fuel injection lines to 20 N m (15 lb ft).
Never close a return line of the fuel system while the engine is running. Damage can be caused to the fuel injection pump.
11. The engine should start. If it does not, repeat steps 1 - 10.