Topic: cb 550 electrical problems (lights - electric goes on/off suddenly)

[poeperman]

Dear members,

if I turn the key to start, sometimes the control lights (neutral/oil/..) don't light up, and the bike is unable to start. If pull the clutch however, the control lights light up and the bike is set to go.

It also happens that, while driving, my gauge lights and taillight go out, and my headlight goes dim. Accompanied with a little stutter in the engine. It's like the engine stalls for a split second and then goes on again.

I changed my battery which only had about 10v @ idle with a new unit but that didn't help..

The bike only rides about 70 mph topspeed but i guess thats due to filthy carbs.

Greets

[seanbarney41]

best guess is the ignition key switch...I am guessing you have a model with the key switch located in between the gauges such as any year 550f or a 77/78 550k.  Actually, all 70's Honda key switches can cause problems but the aforemnetioned models are particularly notorious.   There are threads about how to fix it if you do some searching.  I have had better success just replacing them with good used parts.

[calj737]

It may also be something as easy as a loose ground wire. From your battery, trace the ground cable to the right side of the frame, and insure it's fully connected and clean. Corrosion will effect everything you've described, and nothing is excluded from needing maintenance (connectors, clutch safety switch, switches, fuse panel, etc).

One other thing: your bike may have a side stand safety switch installed. These are notorious for "grounding out" and killing the bike, or preventing starting to.

[poeperman]

it's a '78 F-model, guess I'll have to check the grounds then!

So I just have to follow the cable that runs from the minus pole all the way to the front/back and clean/reconnect all ground connectors?

Thanks for the tips!

[calj737]

You should certainly do that, but it's a very good idea to the entire harness and all the switches. Takes some time, but rewards you with a proper and reliable electrical system.

[strynboen]

there are often a ground under the tank from main harenes to frame,,use to be near the coils

[Mr. Mike]

I like Barneys answer. My source of trouble was the ignition switch itself. Handle bars to the left...all is OK. Bars to the right...everything's dead. Those cables and the brake line jammed behind the head light bucket can press hard enough against the switch body can cause trouble at any steering range.

[tkarahalios]

I had a similar problem and figured out that the issue was with the main wiring harness. Right behind the headlight bucket the cable dips to provide slack for steering. If I squeezed the cable there with my fingers the lights would flicker. Turns out there were some 40 year old factory solder joints on ground wires in that location of the harness. They were intermittently making contact making my lights to flicker unexpectantly. A couple of butt joint connectors and a little heat shrink and all is good now.