Topic: Wiring on CB550K

[lizard5504]

I have a 1973 CB550K which I received in boxes and am making a cafe bike out of. When I started wiring up the bike (stock harness), I ran across an oddity (to me) in the wiring. While hooking up the wires for the started, I found that there were no wires to hook up the starter relay. After looking at the wiring diagrams I found that none of them shows this bike having a starter relay. There is a magnetic starter switch and I am guessing this has taken the place of the old style relay. However, I can't see how this will work. There is no way to hook up the starter cable without a relay in the system. The wiring diagram shows the positive lead  going to the  starter and that can't carry enough current to operate the starter. I have a 1972 CB550F parts bike which has the relay and wires to hook it up so I guess this is something just the K models have. I would appreciate if some one could clarify this for me. Thanks

[iron_worker]

A relay is a magnetic switch. 

Pressing the start button applies a small amount of current to the starter relay (magnetic switch) through the small gauge wires (one power, one ground). The current flowing through the small gauge wires is enough to energize a magnet inside the switch and draws contacts closed which completes the circuit to the starter motor through the large gauge wires.

The large positive cable off your battery should go directly to one pole of the relay. The other pole of the relay hooks directly to the starter.

IW

[Bankerdanny]

I am confident that the wiring for the F and the K are the same. In fact everything about the F and the K are the same except the tank and paint details, the exhaust, and the carb jetting.

It is more likely that some PO modified the harness for some reason to remove it in order to fit different controls.

[iron_worker]

Possibly went to a "kick only" type setup.

IW

[TwoTired]

In the US, there was never a 73 CB550 model, and there is no published wire diagram for such a beast.
The Cb550 model began in 74.  All prior models were CB500.

Also, in the US there was never a 72 CB550 F.  No wire diagram for that either.
The US CB550 F models spanned 75,76, 77 only.

I wonder what you actually have?