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Hello everyone, I recently purchased a 1976 CB200 and I need to replace the ignition coil. I've found a few on eBay but none or oem spec and I can't seem to find one elsewhere. I was wondering if there is a good source out there for oem or nos parts?
 

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wondering how this ever turned out...
i'm looking for an ignition coil but the 175 as well as the 200 looks impossible to find in the u.s.a.
suggestions or links deeply appreciated
 

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Should have a 1.5 ohm coil. i just swapped my oem coil for an aftermarket 1.5 ohm Dyna coil this season. Seems to work better than the original, and have put about 800 miles on it. Not 100% sure of the reliability yet, I would have to get back to you after doing more riding.
 

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mfdemasi said:
Should have a 1.5 ohm coil. i just swapped my oem coil for an aftermarket 1.5 ohm Dyna coil this season. Seems to work better than the original, and have put about 800 miles on it. Not 100% sure of the reliability yet, I would have to get back to you after doing more riding.
If you have a point ignition, do not use less than 3 ohm resistance coils. Lower resistance increases the current draw, wears out/ damages points faster, and draws more current, often causing the battery to drain faster than the alternator can charge it.

If you have an electronic ignition, then follow the recommendations of the maker. CDI type ignitions use less than 1 ohm coils.....


There is no real advantage to lower resistance coils. You can get high voltage sparks from a 5 ohm, a 3.5 ohm or lower, as long as the coil is designed to do it. So lower resistance do not offer more performance...

You should always pick the right resistance coils for the job for reliability and consistence performance.
 

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mfdemasi said:
Should have a 1.5 ohm coil. i just swapped my oem coil for an aftermarket 1.5 ohm Dyna coil this season. Seems to work better than the original, and have put about 800 miles on it. Not 100% sure of the reliability yet, I would have to get back to you after doing more riding.
Stock is 3ohm for a reason

The 1.5 ohm coil should produce a higher voltage at the spark plug
BUT
at a the cost of duration
So a 1.5 ohm coil might produce 50,000 volts but the spark has short duration
A 5 ohm coil might produce lower voltage but the spark has a Long duration
Happy compromise 3ohm
If the plug only needs 10,000v to fire then the extra 40000v from the 1.5 ohm coil is wasted
what you want is a spark that is stong in both bright and long lasting
Also the lower impedance on the 1.5 should mean that the coil charges faster which puts a strain on the ignition system. Now if your running a total loss race bike with a 14000rpm redline then a 1.5 ohm coil will charge faster which is what you need because theres less time between firing and you trade a long duration spark for a fast charge
at a high rpm the coil shouldnt over heat but on a steet bike all the time away from redline will put extra ( unusable ) energy into the coil and they melt
Don't put a 1.5 ohm coil into a cb/cl200 unless you plan on redesigning the whole wiring harness to suit
 

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I picked up an Emgo coil off ebay and haven't put it on my bike yet - sprint66 said it would work fine, but like the accel coil mentioned in the other post it does need some modifications to get it to fit right, at least in a cb200/cl200 frame (mounting posts are set too narrow on the Emgo coil, so I just need to fabricate an extender to reach the stock mounting holes - should be easy enough).
 

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Discussion Starter #9
thanks everyone for your replies, i ended up getting an OEM style coil that works pretty well. currently having some issues getting it fined tuned; I redid the carbs and replaced the air filters with pods. currently trying a few different sized jets but thats all for another thread.
 

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Simo said:
mfdemasi said:
Should have a 1.5 ohm coil. i just swapped my oem coil for an aftermarket 1.5 ohm Dyna coil this season. Seems to work better than the original, and have put about 800 miles on it. Not 100% sure of the reliability yet, I would have to get back to you after doing more riding.
Stock is 3ohm for a reason

The 1.5 ohm coil should produce a higher voltage at the spark plug
BUT
at a the cost of duration
So a 1.5 ohm coil might produce 50,000 volts but the spark has short duration
A 5 ohm coil might produce lower voltage but the spark has a Long duration
Happy compromise 3ohm
If the plug only needs 10,000v to fire then the extra 40000v from the 1.5 ohm coil is wasted
what you want is a spark that is stong in both bright and long lasting
Also the lower impedance on the 1.5 should mean that the coil charges faster which puts a strain on the ignition system. Now if your running a total loss race bike with a 14000rpm redline then a 1.5 ohm coil will charge faster which is what you need because theres less time between firing and you trade a long duration spark for a fast charge
at a high rpm the coil shouldnt over heat but on a steet bike all the time away from redline will put extra ( unusable ) energy into the coil and they melt
Don't put a 1.5 ohm coil into a cb/cl200 unless you plan on redesigning the whole wiring harness to suit
 

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Simo said:
mfdemasi said:
Should have a 1.5 ohm coil. i just swapped my oem coil for an aftermarket 1.5 ohm Dyna coil this season. Seems to work better than the original, and have put about 800 miles on it. Not 100% sure of the reliability yet, I would have to get back to you after doing more riding.
Stock is 3ohm for a reason

The 1.5 ohm coil should produce a higher voltage at the spark plug
BUT
at a the cost of duration
So a 1.5 ohm coil might produce 50,000 volts but the spark has short duration
A 5 ohm coil might produce lower voltage but the spark has a Long duration
Happy compromise 3ohm
If the plug only needs 10,000v to fire then the extra 40000v from the 1.5 ohm coil is wasted
what you want is a spark that is stong in both bright and long lasting
Also the lower impedance on the 1.5 should mean that the coil charges faster which puts a strain on the ignition system. Now if your running a total loss race bike with a 14000rpm redline then a 1.5 ohm coil will charge faster which is what you need because theres less time between firing and you trade a long duration spark for a fast charge
at a high rpm the coil shouldnt over heat but on a steet bike all the time away from redline will put extra ( unusable ) energy into the coil and they melt
Don't put a 1.5 ohm coil into a cb/cl200 unless you plan on redesigning the whole wiring harness to suit
I think you mixed up some terms. A resistor will increase voltage, but reduce duration on the secondary side. On the primary side, things are a little different. Lower ohm is higher amp draw. The secondary voltage is not directly related to the primary resistance. The secondary voltage is dependant on the ration of primary windings to secondary windings. So lets take a 1000 to one ratio. Lets say 10000 turns on the secondary and 10 turns on the primary (1000/1 ratio). At 12V, that gives a 12,000 volt spark. Assuming the 10 turns is 5 ohm resistance, Lets reduce the turns to 5 on the primary. Now the resistance is half. But the ratio went up to 2000 to 1. You get 24000 volt spark...but the current went up 2X more on the primary side.

There are some other considerations, but this is the generalized theory. In actual practice, the capacitor also adds some current to the mix, increasing the saturation of the magnetic field.

Whether you have a 1.5 ohm, 3 ohm, or 5 ohm the saturation time (dwell) is the same because on a point system, the points remained closed for the same amount of time. However, the points are carry more current with lower resistance coils. That causes them to arc and pit and heat up more too.

If you do not have a miss, that is, the present ignition system (when in good shape and adjusted properly) ignites the mixture every time, more spark voltage does not help. The reason racers use lower resistance (higher secondary/spark voltage) is that a higher compression engine, with the large valve overlap and high RPM running, need higher voltage sparks to ignite the mixture. A stock bike does not benefit much, if at all, if the normal voltage is doing the job.

Putting a high voltage, low ohm coil when not needed is like putting V rated (149 MPH rated) tires on a CB200. They are nice, but really offer no extra speed capability to the bike....
 

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Hi Richard
I'm happy to be wrong, its the best position to learn from
As it was originally explained to me..... IIRC :D
As you rightly state the primary and secondary are related in the same way a wire wound transformer more windings on one have a proportional affect on the other.
And as you say a spark travels more easily in a vacuume so as pressure rises so does the need for higher voltage
A lower resistance ( 1.5 ohm) to the primary side gives more time for the magnetic field to saturate the so that when the points break open the field is excited as it can be. As rpm rise the faster the field reaches saturation the better, as the greater the field the stronger the collapse which obviously affects the output on the secondary side. As the primary resistance increase the ability to saturate the field lowers, but with ,as you said the, benefit of less draw and therefore less heat . On a low resistance coil the stock dwell angle means that (at low rpm at least) you're adding unusable energy to a saturated magnetic field and that energy becomes heat because it can't become magnetism.



The length of time the spark is bridging the plug gap is relative to the speed in which the magnetic field collapses (not dwell which is field building ) .When the field collapses it does so into both the primary and secondary windings ( though the primary would obviously induce far less) but the resistance in the primary affect the speed of collapse slowing it and lengthening the time the spark bridges the plug gap. So a longer spark duration



But as I'm neither an electrician or even particularly well versed in physics I may have been more swayed by who was teaching me than if he was right

Thanks for setting me straight
 

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I didn't even get into the effect an inductor has the timing. Also the energy of a hotter spark comes from the energy input. In the case here, energy is watts, amps*volts. Since volts are relatively fixed, more energy = more amps.

The time to saturation as well as the rise time of the secondary voltage have a lot to due to the Contruction of the coil, the shape and location of the core, even how close other iron items ( the frame) is located.

I work in field that uses VFD and all the filtering and effects wire lengths, LCR filtering and alike. The coil system, while physically simple, has a lot of components that affect how the spark is generated. The coil is an inductor, there are resistors in the circuit as well as capacitance so the system as a whole, electrically, is quite sophisticated

suffice to say, if your system, before a component failure, was working well , major changes may adversely affect the outcome. Unless there is a specific reason, the original coil spec is fine for our application and replacing like for like avoids unintended consequences. Like overtaxing generating systems, wiring capacity or point current capability.


Sent from planet Earth using mysterious electronic devices and Tapatalk
 

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3ohms stock for a reason was my conclusion too, even if my argument was based on false logic

So can the lenght of spark duration ( across the plug electrodes) be altered? Or is that another one I can chalk up to more stuff that made sense when I was told, but is altimately not worth ....
 

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Yes....using resistor HT wires or a resistor plug or cap lengthens spark duration....
However, this is a compromise....longer duration means weaker spark energy at any given microsecond of that duration....
Again, it's all about an ideal balance of the two aspects for the engine's needs.....
 

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Ok that is probably where at least some of my misunderstand lay I assumed that it was the increased resistance on the primary side 1.5/3/5 ohm that led to a longer duration spark at the plug I wasn't thinking it was the 5 in each plug cap

When the points open and the magnetic field collapses What stops the fields energy from dissipating through/into the lower resistance of the primary coil?
Or does it, but at a level proportionate to the number of windings ?
So Richards model would have 1:1000 so each 1000v at the secondary =1v at the primary as the field collapses

Thanks S
 

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The capacitor (condenser) absorbs that back emf and stores it. It serves 3 purposes. 1. Store the voltage generated on the primary coil
2. Act as the conduit to ground for the secondary coil. If you notice, with the points open, there is no direct ground for the HV side
3. As part of # 1&2, absorb the Transient spike as the point open so there is less arcing at the points.

Capacitors, unlike inductors, allow potential to pass at first, then slowly becoming a block act as an open switch. Inductors act as a block at first, then allow current to pass.

So when the points open, the coil is reducing current flow at first, while the capacitor is essentially at the instant, a straight shot to ground. As the voltage builds in the coil, the capacitor stops current, and the coil builds voltage faster. When the voltage at the spark electrode reaches a high enough point, it jumps the gap. When you imagine all the timing of inductors building charge and capacitors storing charge, there is quite a bit of physics going on. All in micro seconds.

Like the bartender told the neutron when the neutron went to pay his bar tab: for you? No charge!


Sent from planet Earth using mysterious electronic devices and Tapatalk
 

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Thanks Richard
Always a little late to the party I had a DOH! Moment on the ride home from work and put togeather in my brain how the condenser buffered the current for the closing points reducing the arcing on the surfaces .
Does that mean if you were to use a fancy Hall effect trigger ( pamco etc ) that you would also gain some small messure at the secondary side as the condenser would simply become ground and ALL the induced current would be running to the plugs?

Thanks again for taking the time to straighten the kinked lines of my logic?
 

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?"sonreir" said:
The purpose of the diagrammed circuit is to provide EM flyback protection to the microcontroller. Under normal operations, every time your coil is fired, tens of thousands of volts travel along the HT lead (aka plug wire) to the spark plug. These voltages are high enough to jump the gap in the plug and create a spark. Common knowledge. What isn't commonly known is that several hundred volts are also discharged from the primary coil back up the points wire to the point that fired the coil. In the standard Kettering design, the condenser (basically a large capacitor) helps to absorb some of this voltage and prevent your points from wearing out too soon. No such option when dealing with digital electronics as the voltage levels are still too great. What we have to do, instead, is create a high-voltage one-way system to allow the coil to still be trigger but also prevent any flyback from cooking our transistors and microcontroller.?
Just read this and think that sums up my question

A little like the combined bar tab from a proton and electron :D

Thanks Richard / Steve.
 

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Looking for an ignition coil for my 1975 CB200T, I'm not sure if the unit itself has any issue but the wires are brittle and insides turned to black ooze and it's not to kind of coil you can just replace the wires. I have not problem using aftermarket but I know nothing about electrical stuff, where have you all found the info on the stock coil being 3ohm? Any suggestions for a replacement? If I have to extent the mounting brackets that's fine. As long as it works correctly with the rest of the bike.
 
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