Topic: Broke down. Stuck. Need tech help.

[Billy Bones]

My CB550 is blowing the main fuse. When I pull the headlight bulb, it won't blow. When I plug it back in it will. This bulb has only got the hi beam working. Is it possible that the filament from the low beam side is shorting and blowing the fuse?

Also, seems like someone has required it so that the power to the light comes from the main fuse and not through the headlight fuse.

Been stuck here for 3 hrs.

Billy

[onepieceatatime]

I would think it is more likely the switch is shorting to ground than the low beam filament.
I as far as being wired just through the main fuse and not headlight fuse, POs do silly things.

If you are stuck somewhere because of it, I would just run the high beam until getting home, then check out the wiring and switch.

[Billy Bones]

Only one beam works. When I wire it direct to the battery, the pos wire gets hot and melts.

[Lavis500]

Pull the headlight and disconnect the bullet connector for the low beam - white.  If your low is shorted out, that'll remove it from the circuit.  Ride it on HI all the way home.  Troubleshoot more tomorrow.

[dave500]

i found a trunk light blown that still drew current enough to flatten a battery?get a new globe.

[Billy Bones]

So, I got a new bulb and the fuse still blows. Hooked it up without the socket and the fuse still blows. This has an H4 bulb, I dunno if they draw more current or no. Hooked up an old school bulb and it blew the fuse much slower, so I rode home with it like that, and turned it off and on as I rode trying not to blow it.

It seems to me that there is a short somewhere and that having the halogen light adds too much draw and it blows. Does that make sense?

[dave500]

oh ok,,the trial and error,,might be in the switch?,,h4 shouldnt be a problem(so long as its not say 120 watts!)the stock old school one might be say 35 watts?,,still its some draw via the switch,,bad connection at the fuses?id go over every single connection on the bike if they look grubby.

[OldSchool_IsCool]

To troubleshoot without dumping a whole paycheck into fuses, replace the fuse with a 12v light bulb. The bulb will glow bright while the short is active.

With key on, kill off, wiggle wires, flip switches, unplug/replug sub harnesses until you find the combination that brightens/dims the bulb. Concentrate on that wire/switch/harness until you find the short.

[Duanob]

Sounds like you have some rewiring to do. If someone changed a bunch of the wiring that's probably where your short is coming from. Here is a good color coded schematic to help you check the wiring. In the process pull a part all connections and clean them and put a dab of dialectric grease on them. After that check your control switches on the handlebar for worn wire casings or bare wires.

[dave500]

is yours an f model?the wiring is slightly different,they have a left and right indicator warning lamp for example,if so the wiring diagram above might be wrong for your model?

[Billy Bones]

I'll chk what model it is tomorrow. I think it is 1977.

[Billy Bones]

I'll chk what model it is tomorrow. I think it is 1977.