Motorcycle Repair: fuel pump pressure

Question
Hi Bill,
I have a 1988 Honda Shadow by 800 that the fuel pump has gone out on. Any idea where I might find a replacement?  How could I find out what the fuel pressure is on the original fuel pump?
Thanks for any help.

Answer
Alan, The 16710-MK7-000 fuel pump number is, indeed, long extinct, but the bottom line is that a fuel pump is a fuel pump on a Honda Shadow 7600-700-800 series bike. You have a fuel line fitting for in and out (from tank to carburetor) which is controlled by one of two systems. Either the bikes have an external fuel pump relay or they have some self-regulation and the control comes from the ignition circuits.

If you have a three wire connector on the pump, then it has a relay that powers it....

http://www.750ace.com/forum/index.php?/topic/6967-fuel-pumpor-relay/

The pump pressure on these small pumps is just a few pounds of pressure. They are more concerned with flow rates than pressure, as you can see from the above link images. The small float valves are easily overwhelmed with excessive pressure that a car pump would provide.

If you find a Honda pump with the right configuration of fuel fittings and wire connections, from another model/year Shadow, it should fit and work just fine. A factory shop manual with a wiring diagram will be helpful for your troubleshooting of the electrical controls, as well as the pump tests. You do want to be sure that you are having voltage to the pump during the ON position of the ignition switch, then as the engine starts to turn over and run. Normally, the pump will prime the system for a few seconds, then shut off until it senses that the engine is running, then continue to supply fuel to the carburetors.

There are several Honda Shadow forums on the web with more specific suggestions, perhaps. I wouldn't concern yourself with trying to find the specific pump for your model, as it was produced.

Bill Silver