Topic: Electrical/charging problem? (CB750)

[callbr549]

My 1972 CB750 died suddenly and without warning as I was riding Friday. Once I got it to the side of the road there was no sign of any electrical power. No lights, no indicator lights, starter wouldn't turn over, wouldn't start by kicking.

I've been searching the archives and read the Clymer manual but am still confused about where to start troubleshooting. Can someone direct me to a thread that might help me get started troubleshooting? Or advice about what to check first?  Cleaning contacts seems to be a common thread -- how do you clean contacts?

[KingCustomCycles.com]

You have a main fuse that will kill everything, start there.

[mystic_1]

You have a main fuse that will kill everything, start there.

Agreed, also check your battery but a sudden total failure like that is more likely a fuse or wiring problem.


mystic_+1

[Bido]

Had that happen to me and turned out to be the ignition switch got a new base form Partsnmore $12 you might try cleaning it there is not much but some springs and contacts.

Good Luck
Bido

[callbr549]

This turned out to be the fuse. It didn't look blown -- the metal piece inside the glass tube looked intact, but continuity tester showed no continuity. Pulled the fuse out and one end looked melted.

I replaced fuse last night, and will try riding it today. I assume the blown fuse indicates some other electrical problem, so I'm not sure how I'm going to track that down.

[mystic_1]

Start off by making sure that the clips that hold the fuse are clean, corrosion there can contribute to problems like this.  Next would be to check for corrosion on the bullet connectors and modular plugs.   Even if these don't turn out to be the problem, it's a good idea to clean them up and it's often overlooked.

mystic_1