Author Topic: 1978 cb 400T major electrical trouble  (Read 1273 times)

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Offline fmctm1sw

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1978 cb 400T major electrical trouble
« on: October 21, 2007, 11:51:31 AM »
Picked up a mostly complete '78 400T from a local guy.  Real good compression and picked up set of carbs off eBay.  The story was, the guy lost spark and just dismantled it.  However, I cannot get anything electrical working.  Compounding the matter, I have a climer repair manual that shows detail of the ignition switch.  Appears to be connecting red to brown and dark green to black.  My chilton book says red to black and another.  I've messed around with shorting leads together on the switch.. nothing.  I think I repaired a ground issue at the negative battery terminal but still nothing.  Whats' typical of these bikes?  Black to red?  I would assume black would supposed to be ground.  But from the drawing, dark green appears to be ground for a lot of things.
Quote from: 754
Dude is that a tire ? or an O-ring..??

Quote from: inkscars
This is not a pod thread
This is not a #$%* on my vacuum gauges thread
This is a help or GTFO thread.

1973 CB350F
1973 CB350G
1975 CB550K
1983 GL650I
1973 CB750K3 (http://forums.sohc4.net/index.php?topic=92888.0)
1984 Kawasaki KLT-250 (AKA 3 wheeler of death)
1994 Honda TRX300
1999 Honda TRX250

Offline TwoTired

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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline bryanj

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Re: 1978 cb 400T major electrical trouble
« Reply #2 on: October 22, 2007, 06:33:26 AM »
Kill and ignition switch work backwards to most of the sohc fours as they "ground" the ignition box to stop the spark instead of "powering" it
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline fmctm1sw

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Re: 1978 cb 400T major electrical trouble
« Reply #3 on: October 22, 2007, 03:43:07 PM »
Got it.  I think the combination of cleaning up the battery ground lead to the frame and fully charging my little jumpstart battery did the trick.  Left my jumpstarter charge up for few hours while I took a break, came back and everthing worked!  Well, everything except the horn...  oh well..  And great thread on electrics.  I have it printed and in the garage!

And have spark too now  ;D   
« Last Edit: October 22, 2007, 03:45:07 PM by fmctm1sw »
Quote from: 754
Dude is that a tire ? or an O-ring..??

Quote from: inkscars
This is not a pod thread
This is not a #$%* on my vacuum gauges thread
This is a help or GTFO thread.

1973 CB350F
1973 CB350G
1975 CB550K
1983 GL650I
1973 CB750K3 (http://forums.sohc4.net/index.php?topic=92888.0)
1984 Kawasaki KLT-250 (AKA 3 wheeler of death)
1994 Honda TRX300
1999 Honda TRX250