Author Topic: ignition coil resistance  (Read 4091 times)

Offline elbandtioCA

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ignition coil resistance
« on: May 08, 2008, 03:32:32 PM »
well I had recently posted on here about an engine noise...so I was having a friend who knows a bit more about bikes than I do listen to it.  What he thought instead was that the bike wasn't running correctly at the low rpms...like it stumbles if you really give it throttle and doesn't idle as smoothly as it should.  From what I've heard about b4s I thought having no low end power was normal, but he thought it was running like it had a weak spark/not running on all cyls.

So I decided to test the ignition coils following the instructions in the manuel.  What I found is that the resistance between the plug caps, in both coils was about 40ohms, which is the range.  But the resistance between the leads where the spade plugs fit (is this the primary or secondary coil?) was at 0 ohms on both coils, rather than within the specified range of 2.5-3.8 ohms.  So does this mean that the coils are shot?  Would it explain stumbling/rough idle and very flat low end?  The high end seems to pull just fine.

it occurs to me, however, that it would be weird for both coils to bad at the same time...now I'm thinking I should test the tester...

« Last Edit: May 08, 2008, 03:39:27 PM by elbandtioCA »

Offline Banditmax

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Re: ignition coil resistance
« Reply #1 on: May 08, 2008, 03:46:13 PM »
Yeah that is the right measurement your making for the primary resistance. If they are 0 ohms then i think you may have a tester problem cause generally when coils go the resistance rises. I replaced my coils with a set from a 2006 gsf650 not the watercooled one but one of the last air/oil cooled bikes.