Topic: CB550F Died While Driving. Electric Issue

[MattyBoz]

Hey All,

My CB550F died the other day as I was showing up to work. I was able to park it and leave it there in a secure location, but I haven't been able to revive it. Here's what I know and what I've tried:

-It died while accelerating in first gear.
-When I turn the key over, there is no electric flow. No headlamp. No neutral light or meter backlights on the dash.
-My ohmeter said I have 13.02V coming off the battery
-I put on a brand new stator and field coil in September. The battery and rectifier/voltage regulator (2-in-1 system) were both put on a year and a half ago by the previous owner. The charging system has been fine since the new upgrades were carried out.
-The battery is always on a battery maintainer when it is parked at home.
-I went on a 250-mile ride around Washington two days prior with no issues other than the bike chugging air for a hot minute on the highway because I left the choke slightly open at the start of the trip.
-I took the OEM ignition switch off the bike and took the whole thing apart. I cleaned up the minimal corrosion and gunk inside it. All the contact points were in excellent shape. The bike still did not show any signs of life when I turned the key over upon reinstallation.

I've got no idea what's wrong with it. I've only owned the bike since July of '19, so I'm somewhat of a SOHC newbie and would love any input that isn't repetitive of the measures I've already taken. I'm hoping it's a simple fix (i.e. new battery). Thanks in advance for any help or advice you have to offer!

[bryanj]

1st check is batt voltage at red wire of ignition switch

Yes then is batt volt at black wire of ign switch when turnen on
No check fuse

[Alaxy Galaxy]

On my 400, the main fuse got so hot that it unsoldered itself at one of the metal ends. I put some conductive paste on all the connectors on the bike and it stays cool now.

[robvangulik]

You ride a bike and drive a car! (originates from riding a horse and driving a carriage, or better driving the horses from behind)
I'm quite sure changing a simple fuse will get your bike going again, just be sure you know why the fuse blew in the first place...

[Flyin900]

If it turns out to be the fuse then replace them all as they are 40+ years old and I have seen fuses that appear intact visually, yet when you ohm meter them they are open. Also check for corrosion in the fuse holder clips too since this tend to develop over the years in all single connectors and block connections.

[Bankerdanny]

The 77-78 550K's and all 550 F's have a known issue with the ignition switch that causes this. I had the same issue at a stop light with my '77 K. It just flat died. Here is the thread about it:

http://forums.sohc4.net/index.php/topic,92602.msg1033142.html#msg1033142

It's a really easy repair.

[BenelliSEI]

+1 to bankerdanny! Same experience on my K8. When inspected (destroyed it), the switch was worn internally and literally fell apart inside. That bike also has a problem with the fuse box. The main fuse overheats and melts the base. The fuse clips snap in thru’ the back of the base. As they melt in they get looser, hotter, looser, hotter! Pop the back and have a look, it’s obvious. Replace......

[MattyBoz]

Thanks for the help y'all!

The weirdest thing was happening with the bike. Turned out the left turn signal had blown out and so had the fuse for the main electrical line. It took me two more blown fuses on the drive home to realize that the bike died every time I went to turn left and had my signal on. The left turn signal wasn't blinking, even on my dash, but the headlight and 'neutral' light on my dash were blinking at the rate the turn signal normal blinks. Now that I yanked out the cables to the turn signal (I'm waiting to replace the whole signal because the socket also blew out), the left rear signal works with no problem and the headlight is no longer flashing.

If any of you knows why my turn signal would be blowing out my fuse and rerouting the blinking function to my headlight, I'm open to hearing about it. Otherwise, I'll probably leave it as is. The bike works fine now, minus a front left turn signal.

-Matt

[bryanj]

If it was shorted direct from feed to ground that a dead short so fuse goes

[Stev-o]

Sounds as if you have a wiring issue within the "rats nest" [headlight bucket]