Question about coil resistance

WideAWAKE

Single Fins and Twin Cylinders
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My cb500 has sat for about a year. Getting ready to sell it.

Wheel it outta the shed. Doesn’t wanna start, when it does, runs like a dog.

Go through the carbs, no real gain.

Test coils, right side has resistance in spec, fires with good spark.

Left side, I get no reading at all, primary or secondary.

Got a coil on order but, I’ve never had a coil with no reading at all.

Did it just fry all connections internally, like a blown fuse? Has no connections any more?

Someone with a brain (I lack in that department) understand what’s goin on?
 
Electrical parts are funny. They can be fine one minute then in the blink of an eye, poof. Perhaps there was some small factory defect that hung in there until a hot or cold spell made the material expand or contract and severed any connectivity or maybe last time it was ridden it picked up a road gremlin.
 
Rather than start a tread I'm gunna ask here.
I feel like it's time for a new coil, I'm going to go threw my ignition and charging soon. It's charging a Lil weak. I'll probably do the Auto reg and separate rec from link in tech.
My question is, will a higher resistance create a stronger spark? Mikes lists 3 different coils for my 1980- from a quick search the green coil is at the top of the range. Would I get the same fuel burn and consistency as I would w 1.6ohm amd and a 3.3ohm resistance?
Also I notice the 1.6 is listed as high output and there is a 2.4 right next to it. Does resistance listed have a direct result on spark. I know there is primary and secondary resistance, which only the green one states both.

https://www.mikesxs.net/motorcycles...on-coils.html?product_list_order=name.keyword
 
My cb500 has sat for about a year. Getting ready to sell it.

Wheel it outta the shed. Doesn’t wanna start, when it does, runs like a dog.

Go through the carbs, no real gain.

Test coils, right side has resistance in spec, fires with good spark.

Left side, I get no reading at all, primary or secondary.

Got a coil on order but, I’ve never had a coil with no reading at all.

Did it just fry all connections internally, like a blown fuse? Has no connections any more?

Someone with a brain (I lack in that department) understand what’s goin on?

Dont know anything about that bikes electrics ..So this is tentative speculation.
But i try to fix old HiFi at times
An electronic or electric equipment that has been powered off :May take some time to " wake Up "
Especially capacitors can take many hours to recharge.
Again not sure if that is what happened here.
But if capacitors in a Electronic board and ignition box are down Upon Power up the circuit are not operating at design point.
That can affect how the transistors operate they have a designed operating point.
And on HiFi they can fry going open Circuit or short ..Circuit And then ( Thinking out loud )
Load the coil ..fully ..without stop and not all coils can cope with that
Boyer Bransden fex says to not keep on kicking with power on because the coil can cook.

So when the new coil is there .Some caution is advice able ..On HiFis one uses " Dummy Loads " on the output
resistors that can take the power should something be wrong ..Instead of the loudspeaker that will fry.

f not electronic on the CB 500 there is the capacitor at the points that can take time coming up. If defect
 
A lower resistance coil will draw more current than one of higher resistance. If you're running points in a 12 volt system, you normally would use a coil closer to a 4 ohm resistance to keep the current load on the points and charging system at a reasonable level. Electronic ignitions, with current-limiting circuitry, can use a coil with lower resistance. Current draw is a good measure what the output of the coil is at the plugs, you need the right resistance to get adequate spark energy without overloading things with too much current draw.
 
If you change your coil resistance with points you would need to match the condensers to the new setup.
There's a formula somewhere......
 
Lotta guys here use used Honda coils on their XS with TCI ignition.
On a two tower coil secondary is measured tower to tower not to ground.
I'm guessing this is a 4 cylinder CB500? or is it the twin?
 
It’s a 500t (twin)

My right coil measures good.

I just got nothing on my left. Just never had a coil that measured nothing.

My new one showed up today so I’ll swap it In tomorrow and see where I’m at.
 
Single output coils usually have a single point where the pri and sec are tied together. If it breaks at that point, neither side will show resistance.


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