YZ426 / Busa / GSXR / R6 coil question

i've searched a bunch, and keep coming up with the same results...

everyone "SAYS" that a GSXR coil will work instead of a busa coil, but nobody that i've found actually has USED a GSXR coil.

I know an R6 coil is the same as a Busa (have a buddy who works on bike use an R6 coil on a Busa when he couldn't get ahold of a busa coil), but haven't had any luck on teh GSXR coil.

Me and a buddy both got GSXR 1000 coils and connectors for cheap. He tried his the other day and says all his bike does is sputter and pop. I didnt try mine after that.

Does anyone have a concrete answer to the G1k coil working? or is it all stipulation?


I would also like to know, my moose stator just isnt cutting it, lights are very dim!

i think you're confused? the coil that i'm referring to is the ignition coil, not the lighting coil or stator.

i.e. the coil that sparks the spark plug.

If your moose stator isn't cutting it, maybe its your setup? you running the system A/C still, or swap over to a DC regulator / rectifier w/ a battery in the system?

Oh my bad!!!

I do have a regulator/rectifier and a battery.. I have a baja designs kit on my bike..

i've searched a bunch, and keep coming up with the same results...

everyone "SAYS" that a GSXR coil will work instead of a busa coil, but nobody that i've found actually has USED a GSXR coil.

I know an R6 coil is the same as a Busa (have a buddy who works on bike use an R6 coil on a Busa when he couldn't get ahold of a busa coil), but haven't had any luck on teh GSXR coil.

Me and a buddy both got GSXR 1000 coils and connectors for cheap. He tried his the other day and says all his bike does is sputter and pop. I didnt try mine after that.

Does anyone have a concrete answer to the G1k coil working? or is it all stipulation?


I doubt it will work properly. Why are you wanting to use one anyway?

Should work fine, I've installed many Lincoln Continental coils on 426's with very good results, must have good grd, make sure the coil contact is actually touching the spark plug top. You can go to Motoman393 website and look at the tech articles of the coil kits I was selling to see the wiring and instructions. Mike

What was the year and engine size of the Lincoln coil (and is there an equivalent Ford coil?) ? Were the terminal connectors also available?

I work in a Lincoln Dealership, so I have several left, and have cut up old wire harnesses for connectors. 4L7Z-12029-AA coil #, Wiring from junk Yard, Motoman's sight here on TT Has pictures an instructions, That I sent him many yrs ago to post. Mike

I just picked up 4 R6 coils on e-Bay for 10 bucks...1 for my 426, one for the boy's 250, and 2 extra. the coils are from an 01. I have a line on a coil harness from an 06 with all 4 connectors. Does anyone know if the connectors on the coils are the same for 01 and 06? The coil part numbers are slightly different...

ive had a gsxr coil on my 426 for a few months, it popped like crazy, i just aquired a stock coil and put it back on and the bike runs mint again, dunno about the other coils but the gsxr one didnt work well for me.

I realize this is an old thread, just wanted to post some "current" and more complete info for others to find.


Essentially, a CDI ignition is rather different from non-CDI ignitions in that the coil functions as a "voltage step-up transformer" instead of an energy storage device. The CDI box has a capacitor inside that charges up with higher voltage received by the stator charging coil, when the CDI receives the trigger signal from the flywheel it dumps this stored voltage into the coil. The coil magnifies the voltage greatly and this high voltage ends up as the spark in your plug.  If you'd like a more technical read on CDI operation just hit google, there are lots of engineering sites with info on the topic.


The important part to remember here when selecting a different coil for use with your CDI is the Primary coil resistance value.  A higher resistance value will result in less spark energy (because you are adding more resistance to the path that the electricity must take from one point to the other). A lower resistance value will allow more spark energy (you are reducing the resistance in the path). Most CDI coil primaries are in the 0.50 range or below, but some go as high as 2.0 or just under 3.0. 


The Secondary resistance value is not as critical with a CDI as it has much more tolerance of a wider value range. As long as the value of the secondary is reasonably close to your OE spec it should not present any problems.  There are also some other variables to consider such as inductance of the coils, and difference in resistance between the two coils, but that is very difficult to figure without specialized equipment as to what affect it may have on performance.


The YZ426 Primary resistance value spec is 0.20-0.30 ohms (1-ohm scale)

The Hyabusa Primary resistance value spec is 1.0-1.9 - This is much higher resistance than the YZ426 coil, and will result in less spark energy.

The 2003 YZF-R6 coil is same as the YZ426 at 0.20-0.30, and would be a good choice electrically.

The YZ450 cap-on-coil primary resistance is 0.08-0.10 - now that is low! you should get a hotter spark with this vs the YZ426 coil. another good choice.


Will the higher resitance value coil-on-cap parts from various sport bikes work on the YZ426, WR400, etc that use a frame mounted coil? Probably, there are a lot of folks running Hyabusa coils and Lincoln coils without issue. If you want a hotter spark, choose a coil that has Primary resistance equal to or lower than your stock coil.  Too high of a resistance and you'll get weak spark, poor ignition, issues as noted above by previous posters. 


The CDI spark is very fast and powerful but very short. It needs to be powerful so it can ignite the combustion chamber during it's brief moment.  A lean air/fuel mixture typically causes more problems with CDI ignitions than any other type of ignition, so if you are on the lean side and experiencing hard starting or rough running try richening it up.


Coil wiring is all the same for these Denso / Mitsu 2-wire coil-on-cap units. When holding the coil and looking straight at the plug pins, your "hot" pin is the right side pin.  Right pin to CDI coil wire (+), left pin to chassis ground (-).  You don't need a special plug to retrofit oneo these new coils to your existing wiring, you can use the smaller speaker female crimp connectors to slide on to the coil pins, and then some silicon to fill in the plug cavity to keep out moisture.  But it's nice to actually have the right plug and looks more finished. Any of the 2-wire plugs for a coil-on-cap ignition will work, ford, sportbike, etc.   Probably around $10 on ebay if the local auto parts store does not have one for less.

Edited by LA_Thump

Essentially, a CDI ignition is rather different from non-CDI ignitions in that the coil functions as a "voltage step-up transformer" instead of an energy storage device.


All ignition coils are step-up transformers, and none of them are storage devices.

Hi Gray- Respectfully, that is incorrect. There are two main types of ignition systems in use today, the older Kettering system (TCI, IDI) and the newer CDI- Which is largely more popular and better for race / performance applications.


With the Kettering (TCI, IDI) Induction ignition design, the coil is powered all the time by 12v DC and is triggered to collapse to spark by the ignition module. The ignition module triggers the spark by disconnecting the primary coil winding ground connection, and the stored charge inside the coil collapses through the secondary to spark plug, at about 30k volts. This charge is stored directly inside the coil itself, so only an inductive design of coil can be used with this type of system. This type of systen is slower since it takes the coil longer to re-saturate and build a charge after each discharge.


In the CDI design, the coil is not powered. The coil only receives a short high (250 volt) pulse to its + terminal from the CDI module's capacitor and then amplifies that roughly 100:1 to a much larger voltage spike (about 40,000 volts).  A capacitor inside the CDI box is charged by the stator coil (AC-CDI) or battery (DC-CDI), and is what stores the 250v "charge" until it is triggered to send it to the coil by the CDI trigger circuit. This amplified voltage continues through to the spark plug and the capacitor discharge > voltage step up at coil > collapse to spark plug takes place in one quick step.


The charge storage and re-saturation of charge storage only takes place inside the CDI capacitor. The coil only acts as a pass through step-up transformer, but never itself stores a charge or requires re-saturation. This is what makes this type of system fast and better suited for high rpm applications.


This is also why you can only use coils specifically designed for CDI systems with a CDI ignition, and why it is important to note the specifications of the primary and secondary reistance values. The CDI coil recieves much higher short voltage bursts from the ignition at the + terminal and must be able to efficiently pass it through in one fast step, whereas an inductive system provides an interruption to the coil's negative wire to release the coil-stored charge. The inductive type of coil only receives standard 12vDC voltage on the + side and would get toasted by a CDI.  On the flip side, a CDI coil would not work with an inductive ignition since the CDI coil is not capable of storing a sufficient charge, and would require much more voltage at its + terminal than typical 12vdc


(my above info was referenced from Wikipedia and a couple of other resources on ignition theory & design)

Edited by LA_Thump

So all that said- If we are comparing a coil to a battery or capacitor, then true none of them are storage devices in that sense. And yes all types of coils are responsible for stepping up voltage. But for terms of describing ignition operation, the inductive design of coil is responsible for saturation and storing the charge for each discharge, whereas the CDI coil is not. Hence my point of disagreement. I can't think of any better term to use other than storage when describing the key differences between these types of systems and their coils.

Edited by LA_Thump

I repeat, fearlessly, that all ignition coils, whether Kettering or CDI, are step-up transformers, and neither type is a charge storage device, or is even capable of such a thing. 


In both case, the coil consists of a primary winding in parallel to a secondary winding featuring a much higher winding density.  In both cases, the output voltage is the result of induction occurring as a result of the collapse of the magnetic field formed around the primary while current was passed through it.  The only difference distinguishing the two systems is the nature and source of the primary current, which you have accurately described as either being a higher than system voltage discharge from a capacitor (an actual charge storage device), or simply system voltage.


In the Kettering ignition, system voltage is passed through the primary windings.  At the time spark output is desired, that current is interrupted (by something as simple as mechanical breaker points, or as exotic as semi-conductor switching) and ceases to flow.  While current flowed, the primary windings had a magnetic field around them.  Since the current that supported this field ceased, the field collapses, and since the secondary coils are aligned concentrically, the field collapses around them inducing a current flow in that coil.  The voltage of the output of the secondary is directly related to the ratio of primary to secondary windings, and in most contemporary Ketterings, runs at around 20-30Kv. 


CDI systems simply replace the system voltage with the discharge output of a capacitor, not so much for its increased voltage, but for its extremely short voltage rise time, which reduces the tendency of the spark output to be short circuited by semi-conductive deposits on the plug.  Even the relatively high voltage coming from such a capacitor, which can be as high as 300v, is woefully inadequate to fire a spark plug gap in a 12 bar atmosphere.


Coils don't store charges.  If you think they do, you should be able to charge one, disconnect it from a source of electrical power, then read what the stored voltage is. You can do that with a capacitor. 


The main difference between the two types of coils is, on the one hand, the winding ratio.  The inductive coil requires a winding ratio of secondary to primary windings that will step up the voltage roughly 1800:1 in order to go from 12v to 25k.  The CDI coil needs only to go from roughly 250v to 40k, a much lower step up of 80:1.   The second difference is the dielectric integrity of the coil winding's insulation.  The Kettering coil would be unlikely to long endure carrying 250v when it was built to handle 12, and even if it could, the output would be an outrageously high voltage in the neighborhood of 450,000v, which would certainly destroy the secondary windings.  OTOH, the CDI coil simply would not step 12 system volts of the Kettering up to a usable level (only about 1000v). 


Go back and review the article you read again, or backtrack further, and read up on basic electrical capacitance and inductance.  Coils are transformers.  They don't store a charge.

Gray I think we are on the same page and have the same fundamental understanding- the disagreement is only on symantics.  I agreed in my last post that if we are descirbing "storage" in the terms relating to a battery or capacitor, then you are correct and I agree- no coil stores energy in the sense of a battery or capacitor. I am using the term along the lines of "containing" or "developing" the field charge. 


To change the symantics to some degree.  the inductive coil uses the primary to generate and saturate the coil with magnetic field energy. this generated field is discharged at high voltage through the secondary on field collapse. It is not incorrect to use the term "storage" here. The developed magnetic field has to be stored somewhere before it is discharged. 


A traditional ignition coil consists of an iron core surrounded by two coils of copper wire. An ignition coil has an open magnetic circuit, the iron core does not form a closed loop around the windings- this is different than a power transformer. Although, as we know the coil's job is to also transform energy.  The energy that is stored in the magnetic field of the core is the energy that is transferred to the spark plug.  We can use the term storage here correctly.


I'm not trying to over-argue - I think we are both correct here. it is ok to use the term storage as long as were not talking about battery-like storage, which I'm not :D

How the coil core is constructed is of no consequence to the issue at hand, which is the fact that the SOLE function of any ignition coil is that of an inductive voltage stepping device, intended to provide high voltage electrical energy from a lower voltage source. The electrical principals upon which the coil operates in either ignition system are identical; the inductance of a current from one circuit to another.

In both cases, a current is passed through the primary, and in both cases, a magnetic field is formed that surrounds both the primary and secondary. In both cases, the current is terminated, albeit by different means, and thereby, the magnetic field collapses, inducing a current in the secondary. Only the saturation time is different.

The correct terminology to describe what happens in the Kettering coil is not that there is a charge stored, but that there is a current maintained. It isn't semantics; words mean certain things and they don't mean other things. In technical writing, it's a big deal.

It's also important, if one hopes to effectively repair or modify things, to accurately understand how those things operate.

You are correct, however, that one cannot mix coil types among CDI and Kettering types like the "TCI" ignitions on the EFI bikes, for the reasons I mentioned in the previous post.

Sure, no big deal if we disagree on the terminology- It's actually nice to have some good high level banter in one of these forums :D.   I must also remain firm on the point that it it is indeed correct to reference the term 'storage' when describing the operational characteristic of an ignition coil. 


The below excerpt is from Wikipedia, it is a legit page based on facts from accepted automotive workbooks on ignition systems.  The information has been reviewed by the National High Magnetic Field Laboratory. If you crack open some of the dusty old engineering texbooks, you'll find similar references within topic discussion. I figured sharing this might be better than my own opinion, because you know what those are worth (heh).


(Ignition coil basics section ) ..."When the contact breaker closes, it allows a current from the battery to build up in the primary winding of the ignition coil. The current does not flow instantly because of the inductance of the coil. Current flowing in the coil produces a magnetic field in the core and in the air surrounding the core. The current must flow long enough to store enough energy in the field for the spark. Once the current has built up to its full level, the contact breaker opens. Since it has a capacitor connected across it, the primary winding and the capacitor form a tuned circuit, and as the stored energy oscillates between the inductor formed by the coil and the capacitor, the changing magnetic field in the core of the coil induces a much larger voltage in the secondary of the coil."

So I ordered a coil for a 2003 YZF-R6 ($19) and found an ignition harness that has the coil plugs ($6). I will only need one of these plugs on the harness so if anyone else wants one just PM me and you can have a plug for whatever it will cost to send it to you- I'm not interested in making a profit. These plugs work with any coil-on-cap design it seems fairly universal.


I opted for the R6 coil since its specs are identical to the YZ246 coil on the Primary, and rather close on the Secondary. My only concern will be the length of the R6 coil and if it is long enough or too long for the YZ426- I have read the R6 coil will fit on a Hyabusa but you know how that goes with loose info on the internet. 


Will post more when parts are here.  My goal is to try and provide the remaining "missing" information that I have not found in any other related threads, and hopefully the info will make it easier for others to do this YZ / WR coil mod with less worry and figuring out.

This, I believe, is where you got crossed up: "The current must flow long enough to store enough energy in the field for the spark."  It's a very poor way of wording the matter, because no energy is "stored" anywhere in an electrical sense, because when the power source is removed, the magnetic field, being current dependent, ceases to exist.  A capacitor would retain a measurable charge.  More accurate would be to say that current must flow for long enough to raise a magnetic field that contains enough potential energy so that when it collapses, enough current will be induced in the secondary to effect a spark.  The strength of the field depends primarily on the strength of the current applied to the primary, and although there is there is a certain amount of time required to propagate the field, time is much less important. 


To keep things in context, when the article points out that the "current must flow long enough", how long do you really have?  A V8 engine at 6000 RPM fires once every 5 milliseconds, or once for each 90 degrees of crank rotation.  Using breaker points, the practical limit to dwell time, the amount of time that the primary circuit is powered, is 32 degrees.  Using a dual point distributor, that can be extended as far as 35 degrees.  At 6000 RPM, that's not quite 2 whole milliseconds, yet it is "long enough" for a spark to be created by raising and collapsing a magnetic field.  So, any inferences one might draw from reading that that the whole process takes a significant amount of time to accomplish is misleading.

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