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Discussion Starter · #1 ·
Hi guys I have a CB400 "Hawk" engine in a mid-80's Odyssey that was running like a champ last fall, but after sitting all winter, no spark.

I have a junky multimeter(bad leads most likely; new ones on order) and that makes it hard to diagnose correctly, but at this point, I highly suspect that the coil died. I left the key "on" all winter, and also found a stone dead battery, which has never happened before.

Quick question..! I have access to other coils, some old auto coils, Briggs coils, snowmobile coils, etc.... They only have one plug wire, but could one of these be used to test the CB's system for spark? I'm concerned with a gross mismatch and possibly damaging other components(IE: the CDI). All I need is to see one spark to know that I need to buy a new coil and wouldn't crack it longer than necessary.

Can I do that? Thanks!
 

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74 CL360, 81 CM200T, 85, 86 & 87 CMX250. Invisible to cages, treat accordingly. Avoids Road Rage!
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Give it some time. I don't know, therefore I didn't answer. The weather was so nice, I'm sure many have been out riding & maybe still are.
 

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See similar threads, there are many....

HT coil, primary less than 1 ohm
Secondary 15k ohm from memory with HT caps removed.

Cdi can die overnight, ask me how I know.

See similar threads.....
 

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Discussion Starter · #5 ·
Thanks for the responses!
Problem with previous threads is that there are tons, and though the diagnostics are similar, I asked a specific question, regarding trying other coils simply to eliminate the questionable results I'm seeing with my questionable multimeter. Everything I test, I get multiple results.

I know that anything can fail overnight, but I don't have money to throw at it, guessing at various components, not to mention the time lost waiting for components to arrive if they're not the component that needed changing.

Back to me question: can I try another coil, just as a go, no-go test? Thanks!
 

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The ing trigger on the fly wheel tells the SCR gate to open and the capacitor discharges to the coil and grounds thru the spark plug. It may not be the coil but the capacitor. .If you can do an ohm test on the blue and white wires. if they test good. then it may be the CDI. You can use a late model GM set of coils that have a duel lead to test it. They have a spark plug lead for two plugs.

Bill H
 

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If you no longer trust your dmm, get a new one, they are relatively cheap and are versatile...

Check stator leads to cdi for ac volts output, revs rise, AC voltage should rise...

See, read and digest similar threads as more or less all needed info is in them...
 

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74 CL360, 81 CM200T, 85, 86 & 87 CMX250. Invisible to cages, treat accordingly. Avoids Road Rage!
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One thing to add. The CDI is an electronic device that needs to be protected from radio frequency interference (RFI). If you don't use the correct plugs, (resistor type), this can cause a very short lived CDI.
I think everyone is on the right track. The replacement coil test, the voltage test (around 100VAC if memory serves), & especially your VOM. Walmart has a very serviceable one for about $12, good repairs require working tools.
 

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Discussion Starter · #9 ·
Okay, borrowed a reliable meter, and with the coil on the bench, dry, I get 3.3 ohm across the green and yellow wires. On the pinned diagnosis page it states that it should be less than 1ohm, spec being .35 to .55

She bad?

Yes, I run resistor plugs, and mounted the CDI about 6 inches from the coil. Also realize that I started this discussion in the wrong section; my bad!

Sure hope it's just the coil. I can't afford a CDI this year, for this toy, fun as it is.
 

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Picture of the coil, the HT coil that is which is on the bench.

Apart from the lower potted section of the cdi, the units insides are effectively in a Faraday cage...apart from the wires that is...

Your coil is oe, an fl12 from memory ?
 

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Yes, tabulated stator resistance checks, ideally cold and hot, as well a AC volts test, plugs in, and plugs out cos it will spin a little faster, revs rise, ac volts output rise...

Is it you who has the scopes ?
 

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Discussion Starter · #12 ·
Picture of the coil, the HT coil that is which is on the bench.

Apart from the lower potted section of the cdi, the units insides are effectively in a Faraday cage...apart from the wires that is...

Your coil is oe, an fl12 from memory ?

I'll try for a photo later today or tomorrow, but yes, the coil is OE and is "FL 102"

I don't have a scope.
 
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