Author Topic: 1974 CB550 electrical demons won't leave me alone  (Read 406 times)

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Offline oregonjake

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1974 CB550 electrical demons won't leave me alone
« on: June 18, 2019, 12:01:41 PM »
Okay, after carefully reading as many posts here as I could on the SMSU, right hand handlebar switch, starter and solenoid and all related systems and parts I still am in the dark. Let me try to explain...

The right handlebar switch and ignition switch were bad (or so I thought) so I replaced them (Emgo unfortunately) and I am still having the same problem. Before replacing the two switches I powered her up with a fully charged battery and hit the start button. Nothing but solenoid clicking. I rechecked the battery, recharged it and tried again. This time the starter motor spun the engine with no problem but no spark at the points or plugs. New plugs and a careful timing of points...tried again and the solenoid clicked as it did previously. I then addressed the SMSU bypass to see if the SMSU was bad...same result, solenoid clicking.

Then cleaned clutch switch, same result. Bypassed the clutch switch, same result. Also have gone through all connections and plugs, cleaned them and reconnected, same result. Checked all grounds. Now on occasion when I push the start button, turn the headlight on, try the turn signals or the horn (not at the same time) the dash lights immediately go off or dim significantly, only to either come back on bright of their own accord or they stay off unless I turn off and on again the ignition switch.

Do I clean all the connections again, replace a part or pull what little hair I have left out? I am at a loss and I want to ride!

Offline robvangulik

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Re: 1974 CB550 electrical demons won't leave me alone
« Reply #1 on: June 18, 2019, 12:33:40 PM »
Measure the voltage of that battery, couple of hours after charging, and while attempting to start.
It sounds as a battery at the end of its life.

Offline oregonjake

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Re: 1974 CB550 electrical demons won't leave me alone
« Reply #2 on: June 18, 2019, 03:36:29 PM »
(Palm firmly on face) A brand new battery out of the box...bad cell. Sigh. New battery tomorrow.

Thanks.

Offline robvangulik

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Re: 1974 CB550 electrical demons won't leave me alone
« Reply #3 on: June 19, 2019, 12:20:33 AM »
Always, ALWAYS measure a new battery before use..especially if you went for a cheaper brand!
I suppose/hope you have some kind of warranty?

Offline oregonjake

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Re: 1974 CB550 electrical demons won't leave me alone
« Reply #4 on: June 19, 2019, 08:21:10 AM »
The battery came with the bike. It was new in the box, dry and with a sealed bottle of acid. I thought a new battery would be good...it is NOT a Yuasa but the cheap Super Crank brand. Why I didn't think of checking it first...Gaaahh!  I'll get the trade in value but that's about it.