Coil on plug experience.

Has anybody had any long term experience with a coil on plug on a YZ 426? I have installed a set up from a ford car. It has slightly more primary resistance and slightly less secondary resistance. So far seems to run great with better throttle response and hotter spark. Mike

Part Number please??

PM KCHusky and I'll call him to notify him of this post..he has been using probably the same thing courtesy of a Continental I believe...his has been tested under all types of nasty conditions and hasn't missed a rid of that coil on the frame..looks much cleaner on that side of the bike now. Jason

Im with Hick! What did it come off of and what is the part number. Id love to walk out of the Napa store with that part!

I am also interested tell me, tell me, tell me......also Hyabusa Suzuki coil should work....

I'm a lincoln-mercury mech. I used a continental coil and took the boot off of it and cut the stock boot off of the YZ and slid it on. if you are interested I can sell you the whole set up for about $80, including coil, wire connecters, shrink tubing, convolute tubing, and instructions.

It mounts up perfect with some modification, and looks very clean.


[ April 29, 2002: Message edited by: mike dean ]

mike dean,

What are the advantages of a new coil (other than to get it away from the frame)? Does it make the bike faster or start easier? I might have to do this, depending on what others say. Maybe Dubach will let us know in the "new" TTalk section :) Thanks,


So here we go... After obtaining Busa coils from cylinders 1 and 4 they will not fit. I've checked the parts book and all coils for all cylinders for all years of Busas are the same. The Busa coils do not appear to fit, as with the R6 they are about 13mm too long. DO NOT PLAN ON USING BUSA COILS, at least not this PN 129700-4420-10440 (this is the actual decaled PN shown on the coil I'm reading right now).

I obtained coils from another Suzuki. A coworker had them from his roadrace days. He informed me these were off a GSXR750, year unknown. However when the GSXR750 PN was checked it seemed they were the same as the Busa PN. Go figuire!? The PN I have in my 426 that fits without cutting any of my frame is... Drum Roll Please, 129700-3440-10344. This is the actual PN from a spare coil I have.

As for reliability, it starts, it stops. I have had the TY neutral cover for a year so I have never had a blue wire hooked up. The bike has always started good unless I'm tired or lazy.

Three blips and choke when cold, most times one sometimes two kicks. When hot MOST (90%)times no hot start. Restart after cool down usually no choke, no hotstart, and it will most times fire in two kicks.

As for performance...No bog while riding, or idling and grabing a handful (no B.S.). No fouled plugs. Will easily bounce rev limiter in 4th (1,2,3 obviously no problem), 5th pulls hard and long but I have not touched max rpm in 5th on a dirt road but it's close, and besides as my bud with the other coil setup says why do you need more they are already QUASAR FAST. It would most likely hit max RPM on pavement in 5th. I also haven't tried for max RPM in 5th with my stock muffler. I'm fairly confident the stock exhaust would pull to max RPM in 5th. The Canadian pipe isn't as advanced in design but with 2 more inches of muffler it sure won't make your ears bleed.

Unless you can find a salvage yard willing to chop

the harness to get the coil connecter, or are willing to buy a new harness at $300 this mod gets expensive. I had planned on selling the other setups of coil and connecter but have since reconsidered, until I know more are available. It would be best to find a salvage bike and buy all the coils and harness connecters and split the cost four ways. New coils run about $75 retail and one fourth of $300 is $75, so for about $150 if you find four people new is about $150 per bike. Used will obviously be less.

Saves about a light half pound.

For the record here's the bike stats

2001 YZ426f US model

2001 YZ426 Canadian aft muffler (2" longer can and not stepped like stock or the DRD pipe)

2001 stock headpipe

2001 Stock gearing with Renthal chain + sprokets

2001 reworked and jetted carb. (BK mod, MAJ mod)

2001 reworked airbox with Unifilter

SDG seat so as not to slide my butt off the back

Ammoco 93 fuel

Mobil 1 oil

Aeroquip front brake hose

mostly stock with a poser rider


Hayabusa has different lengths depending on what cylinder it's for. I emailed Dubach and he said he just got a set from Suzuki and would let me know which one works when he gets it sorted out. He said the one he's using now (pictured in MXA) was given to him by the factory team and he's not exactly sure what it's from.

I noticed Chad Reed's 250F has the same setup.

Speaking of Dubach... on his website is a kit to make the YZF rear brake have a built in resivor like the CRF's have. It's not available yet but they have a drawing of it.

How do you guys fit the coil-on-plug I can barely wrestle the stocker out, what modifications have to be done to the rest of the ignition?

PMK, I'm interested in the resistance of the coil you have. Measure from terminal to terminal, and from terminal to spark plug lead. Thanks mike

Garrett, I'm still testing the coil setup but it seems to have better snap and just by looking at the spark it appears to be hotter. Ford has been using these for a long time with no problems, makes for a cleaner installation on multi-cylinder engines, is lighter. Mike

Mike, for comparison this is what my elcheapo digital VOM indicated:

"P" lead .1 ohm

Secondary 5.73 k ohm

this is the coil I'm using

The 1300 Busa coil shows

"P" lead 1.3 ohm

Secondary 13.4 k ohm

Stock coil

"P" lead .3 ohm

Secondary 22.9 k ohm with cap installed, this is supposed to be checked with cap off per manual. I suspect the cap contains a resistor for noise suppresion.

I do not beleive a lower secondary value or higher secondary value should have too much affect. If this were a stock coil it obviously would be a concern, but considering this is an entire coil/cap/terminal assembly it's designed to function as a system. We all realize that the stock coil uses a laminated iron core, the cap/coil may use another core material that provides similar output voltages.

I do admit to good starting at all times hot or cold, and the thing runs good. If there were a huge primary difference the primary may become choked. Remember that output is determined by input feild flux collapsing and generating voltage into the secondary. The secondary output is connected to the CDI only at the ground. This is not directed at anyone to insult them so please don't take offense to the above. I just gave my explanation of how a coil produces high voltage.

This is a neat mod but personally I wouldn't lose sleep if I didn't have it. As always more riding will make me a better rider, but cool factor is cool, fast or slow.


The coil isn't fired by collapsing the field on a CDI type ignition. Its fired by a capasitor charging to approx. 300-500 volts then discharged by being grounded by an SCR to fire the coil with an instant burst of voltage off the capasitor.

Thanks Shawn,

I should have thought about what I wrote more, I guess I had too much magneto on the brain. I was mostly focused on the fact that coil output windings are connected to the ground and this is the only connection to the system. Apologies if anyone has been mislead. I hope I've got it right now.


Just curious if anyone else has gone thru with the GSXR coil setup on their YZ.


Shawn Mc, check your PMs, Mike

Matt, sorry about the e-mail, yes it includes shipping. mike

I would agree that matching the stock coil's spec are needed. But I would add this also..

Motoman asked a very good question:

What are the advantages of a new coil (other than to get it away from the frame)? Does it make the bike faster or start easier? I might have to do this, depending on what others say. Maybe Dubach will let us know in the "new" TTalk section Thanks,


The responces were are good, but the need for scientific mumbo jumbo is Bull. simply put all that nees to be done is match the stock coil specs to the replacment or as close to as possible.

Motoman asks what advantages:

I see it two ways:

1: it clears an area to the crab for easier access to the pump screw

2: it clears an area to the crab for easier access to the pump screw

Will it make you go faster, Probably not

Will it make you jump higher probably not

Will it mike the bike Lighter Probably not

Will it Wheelie Better Probably not

Will it look cool Oh Ya

Will it cause some attention Oh Ya

Will it sike out the others that dont have it Oh Ya

Other then That its a cool mod nothing more......

Just my $4.26 worth


Ok, so what is the correct setup for doing this mod????? How much will it cost?

Thats what I have been waiting for

But nobody seems to be posting that info.

Kinda reminds me of my Engineering team here at work

Shhhhhhhh Dontsaynothing maybe they will go away and leave us alone

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