top coils not firing

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rabiticide
Posts: 64
Joined: Fri Jun 20, 2008 4:55 pm

top coils not firing

Postby rabiticide » Sun Jan 01, 2017 5:11 pm

i am trying to get my bike running again and i am not getting spark on two of my four spark units. the top left and the top right as you are looking at them under the gas tank. i am kinda thinking that it is some wiring external to the coils that is causing this problem, its tarp had blown off in the rain and i suspect i need to dry the switches, etc.

but how do i test the coils to make sure the problem is not there? what else, if not the coils themselves what could cause this?

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Folsoml
Posts: 1634
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: top coils not firing

Postby Folsoml » Mon Jan 02, 2017 8:39 am

I do not understand what it is that is not working. You say "two of the four spark units", but there should only be two of them.

As with any electrical problem, I would start by cleaning all the connections. I would then trace the problem back, connection by connection, until you find power.

Also remember that the left coil runs the spark plugs for cylinders 1 and 4, and the right one runs 2 and 3.
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rabiticide
Posts: 64
Joined: Fri Jun 20, 2008 4:55 pm

Re: top coils not firing

Postby rabiticide » Thu Jan 05, 2017 1:33 am

please forgive my misnomers. i meant that the top spark outputs (leading to the sparkplugs) on each "spark unit" are giving no spark. so 1 and 2 have spark, yet 3 and 4 have no spark. i am going to remove them and test them per the most intelligible youtube video, unless someone knows off hand the supposed resistances (if that is how you check them).

thanks
leif

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Folsoml
Posts: 1634
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: top coils not firing

Postby Folsoml » Fri Jan 06, 2017 5:21 pm

Hmmm. I've never heard of a coil in which one of the outputs would fire but not the other. Are the coils themselves free of cracks? Have you double checked to make sure that the problem is not in the plugs or the plug wires?
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

jcasey007
Posts: 225
Joined: Sun Jan 13, 2013 3:38 pm
Location: Stratford Upon Avon - UK

Re: top coils not firing

Postby jcasey007 » Sat Jan 07, 2017 1:07 pm

Easiest way to test is the switch the wires between the coil (primary coils) that will see if the fault is the coil or the 12 volt circuit. If 1 and 2 still have spark then it's not the coil (it will be the trigger/control circuit), if 3/4 now work and 1/2 don't work it will be the coil


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