Author Topic: Can't get rid of electrical demons on my 74 CB550  (Read 1410 times)

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Offline oregonjake

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Can't get rid of electrical demons on my 74 CB550
« on: June 18, 2019, 11:50:26 AM »
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 DarkLinkX5

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Re: Can't get rid of electrical demons on my 74 CB550
« Reply #1 on: September 04, 2019, 04:26:52 AM »
First this section is for "Proven how to's  NOT for questions" but i wont be a dick and help out anyway. make sure you post in the right form section next time.

test your starter.
either short the solenoid or take it off and apply 12v.
I know for my CB550k3 my solenoid was worn but i fixed it by sanding the copper jumper plate inside it. it clicked but wasn't making good contact.

I also had a switch that was corroded and cleaned that up. if i can fix it i'm not replacing it.
« Last Edit: September 04, 2019, 04:31:39 AM by DarkLinkX5 »
1977 Honda CB550k

Offline Menno

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Re: Can't get rid of electrical demons on my 74 CB550
« Reply #2 on: September 04, 2019, 05:25:33 AM »
Sounds like a ground problem.
Check the wire from the battery to the frame. On both sides.
Problem might be there.

Offline DarkLinkX5

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Re: Can't get rid of electrical demons on my 74 CB550
« Reply #3 on: April 08, 2020, 09:06:33 PM »
Did you make any progress on this?

I pretty much solved all my electrical issues and i had a lot of them.
My bike starts up Instantly now, even when cold. I struggled to start cold last year. i was recently able to replace a few ignition related parts that helped a ton.

if you still need help chime in.
1977 Honda CB550k

Offline Keith

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Re: Can't get rid of electrical demons on my 74 CB550
« Reply #4 on: April 09, 2020, 12:44:46 PM »
Sounds like a bad ground. How to check: put positive lead of a voltmeter on neg. battery post. Put neg. lead of voltmeter to ground. Hit starter button, voltmeter should read zero. If not, bad ground.