I have a 1976 CB 750 K6 that I bought last year. It did not have a headlight in it so I went to the local auto parts store and bought a new one. The problem is when riding at night with the low beam on it is not very bright at all but the high beam is fairly bright. The headlight is a wagner halogen type but I'm not sure of the rating. Is there a difference between a motorcycle headlight and a automotive headlight? any comments would be appreciated.
While bypassing all the bike's original 29 year old oxidized connectors and switches can, indeed, make your headlight brighter, I'm not convinced the benefit of doing this is that much greater than cleaning the connectors in the wiring harness.
Check the voltage at the operating headlight with a voltmeter, and compare it to a reading taken at the battery terminals under the same operating condition. The difference is the result of losses in your existing wire routing.
Looking at the wiring diagram for the CB550 K3, there are 9 interconnects, 4 fuse clips contacts, 3 switch contacts in the power routing between battery and headlight.
There are 5 or more connections in the (green) return path from from bulb to battery. That's 21 connections. If each one provides just .1v loss, that's 2.1 volts lost before the headlight gets any power from the battery. I've measured connections with more loss than .1V. All the energy lost by the contacts is wasted as heat and the bike's alternator output power is stolen by these losses.
There is also the rational, that if your headlight circuits are wasting energy so are all the hundreds of other connections in the bike that bypassing the headlight circuits won't address.
Most of the switches in the bike are self cleaning as they wipe away oxidation as they are manipulated. This is true until they wear out from use. The connectors and fuse clips are another story. These contacts are not of noble metals and oxidize over time. The factory did not use anything to protect the connector metals from corrosion like they did for the switch contacts. I use Deoxit on the connectors after I clean them to delay further oxidation. It made quite a difference in bulb brightness and general efficiency of the bike's electrical system.
Cheers,