how to: increase spark power

[ae13291]

hey guys i got this from a xr400 forum, what this mod will do is increase the spark going to the spark plug and help the quad start much easier. ok first thing is remove the spark plug boot out of the spark plug hole,now remove the blck pastic ring on the top of the yellow boot (it will just pop off easily) next while pulling down on the spark plug boot you have to turn the boot counter clockwise, till it comes completly off, now dont force it off because its like a screw, you have to turn it enough so it will come out. next is the hardest part of the mod. you have to pushthe inner black part that is inside the boot out, yu have to get it out from the spark plug side hole, i just put the boot facing down on the table and used my palm to push down on till the black part slowly came out. now unscrew the brass side and when u open the inside there will be a red resister and a spring. i replaced the spring with a piece of copper pipe the same size. i also cleaned all the contact points with a dremel, and i used dielectric grease to reassemble it all back together. now just do everything in vise versa and thats it. here are some pics. sorry i only took pics with my phone http://i158.photobucket.com/albums/t91/ae13291/0304091415-00.jpg

http://i158.photobucket.com/albums/t91/ae13291/0304091415-01.jpg[/url]

there is the resister^^^^

thats really interesting thats the 1st time i've heard of this. Now does it work? Can you feel it?

[ae13291]

well i just did the mod and then it started raining outside so dident ride it yet. but i would say if the quad took a full second to start it probobly takes about half a second to start no, the quad starts so fast that i cant release the start butten fast enough lol. and it seems to have a better rev to it. i also put a new ngk iradium IX plug in the process too

[Dangerous400EX]

How are you going to know if the mod or the different spark plug is whats making the quad run better? You need to only change one variable at a time if you want to know which mod increases performance


Are you saying that the copper is a better conductor than the spring, thereby increasing spark power?

[ae13291]

Originally posted by Dangerous400EX
How are you going to know if the mod or the different spark plug is whats making the quad run better? You need to only change one variable at a time if you want to know which mod increases performance


Are you saying that the copper is a better conductor than the spring, thereby increasing spark power?

well i know the spark plug wont make that much of a differance in starting. the spring was not changed, only the red resister was replaced by a copper pipe of the same size

[ae13291]

wow im surprised nobody has heard of this mod. lol i have to make a before and after video of how fast the quad starts now.

[scuzz]

Originally posted by Dangerous400EX



Are you saying that the copper is a better conductor than the spring, thereby increasing spark power?


A resistor resists electricity and reduces the voltage. So in other words it reduces spark. Keep in mind that this is a good thing for cars with radios as this reduces the engine noise and interference.

IMO in a ATV it doesn't seem as important. As the OP mentioned this should help with starting and make it a little more efficient while running but you won't see any significant HP gains from it.

I'm interested to see if my 700xx has this.

[BigRed44]

I'm still not sold on this mod. Does it help cold starts at all? What are the real advantages of doing it besides faster start?? Seems pointless to me.

[ae13291]

^^^^ bottom line- you are getting more spark to the spark plug and making it start easier, you are also making the plug run a bit hotter then usual witch would gain som power but this wnt be enough to notice. your basically asking why would i want more power or easier starting? its a simple mod

so you actually replace the resistor. idk that could be bad, resistors are made for a purpose usually so whatever is on the other side doesnt fry up. But since its a spark plug idk

[triple b]

I did this on my XR400 and it did start easier.

http://www.thumpertalk.com/forum/showthread.php?t=486419&highlight=resistor

[Homerx]

You don't need to remove the plug cap or the inner part to perform this mod, just use a larger flat screwdriver to unscrew the brass part that clips on to the spark plug, then go from there.

[400ex07]

I was helping a friend with the 400ex that he just bought and I convinced him to let me try this mod. I started it 3 times to kind of get a feel for how long it took to start, then I replaced the resistor with a 4mm stainless steel bolt, cut to the same length as the resistor, and then tried starting it. It was a very noticeable that it started faster and easier as compared to before.

[ae13291]

Originally posted by 400ex07
I was helping a friend with the 400ex that he just bought and I convinced him to let me try this mod. I started it 3 times to kind of get a feel for how long it took to start, then I replaced the resistor with a 4mm stainless steel bolt, cut to the same length as the resistor, and then tried starting it. It was a very noticeable that it started faster and easier as compared to before.

good to hear man, its simple mod and helped it start easier, and im sure it also increased te spark to the tip of the spark plug

A few things I have a interest/concern:
I believe this mod produces a more intense spark with a shorter duration which = a better burn. But compression and ignition advance affect it. With a more intense & shorter spark I believe you need less advance in ignition timing because the flame front builds much quicker. Still researching. i dont know how much of a great spark it produces. Curious to do a 6 degree timing advance, 10:1 piston, and this mod to see if it would knock on 93 with hard/hot riding conditions. I dont THINK this mod does that much but you never know.

[ae13291]

Originally posted by FlewByU352
A few things I have a interest/concern:
I believe this mod produces a more intense spark with a shorter duration which = a better burn. But compression and ignition advance affect it. With a more intense & shorter spark I believe you need less advance in ignition timing because the flame front builds much quicker. Still researching. i dont know how much of a great spark it produces. Curious to do a 6 degree timing advance, 10:1 piston, and this mod to see if it would knock on 93 with hard/hot riding conditions. I dont THINK this mod does that much but you never know.

i understand what you mean, but the part removed is a resister! i tested it again, if im not mistaken it was some where around 6 ohms, if it was a capaciter we removed then it would be just like how you explained it. now without the resister, the spark reaches the spark plug faster thus advancing i maybe even more.

yeah and for the price of a bolt which i probally have laying around I can always just swap it back. I'll probally do that this week and hope it makes for a faster ride come the weekend. Plus if it interferes with the EFI guys that will really be funny. I think its just car radios and such though. So this resister is it resisting the spark going to the plug or an arc back towards the system to protect the CDI?

[ae13291]

Originally posted by FlewByU352
yeah and for the price of a bolt which i probally have laying around I can always just swap it back. I'll probally do that this week and hope it makes for a faster ride come the weekend. Plus if it interferes with the EFI guys that will really be funny. I think its just car radios and such though. So this resister is it resisting the spark going to the plug or an arc back towards the system to protect the CDI?

the resister is just resisting some spark power and causing it for a later spark/weaker spark, the cdi will not get damaged because it has a secondary and primary circuits that energize the electricity and only send it one way, it already has an internal diode to not let the spark travel back. the only disadvantages i see is the spark plug will most likely be worn more then usual, but that is not such a problem because spark plugs will last years and doing this would probobly take 1 year life out of the plug if it is used for 4 years. that is why i upgraded to iraduim p/n i think is 2202 ngk iraduim IX, and it may also cause a hotter spark which in turn will run really good with advanced timing or leaded or higher octane fuel. i currently use a base of 91 octane then add a little more then 1/2 oz of cocentrated lead additive to 4 gallons, then i add some octane booster's i have laying around in the garage. so my fuel is a light pitch red color now.

[crxjarred]

so you are saying higher octain gas is needed would 93 be high enuff and that this is not a good mod with the sparks timen key

Originally posted by crxjarred
so you are saying higher octain gas is needed would 93 be high enuff and that this is not a good mod with the sparks timen key

i'll let you know if it has problems this week with the timing advanced.

[mitchamus]

So would this be like running the monster coil?

[ae13291]

Originally posted by crxjarred
so you are saying higher octain gas is needed would 93 be high enuff and that this is not a good mod with the sparks timen key

the 400ex already recommends 93 or high octane, but if u use regular it will still be fine, higher octane will help increase power tho, so its up to you

[ae13291]

Originally posted by mitchamus
So would this be like running the monster coil?

to be honest i dont think it will increase the spark as much as the monster coil advertises but this will increase spark more then stock, and its a free mod!

[crxjarred]

ok i did this and wow it makes start up soo much easyer and faster and i beleave i felt a power gain but not sure it reved quicker i kno that but i did it a lil difrent i just took some coated wire and flatend the ends and then ground off a little bit so there was some showen then i replaced the spring and the resistor with it so it was just a long peace of copper between them

[ae13291]

good to hear man!

Originally posted by ae13291
now unscrew the brass side and when u open the inside there will be a red resister and a spring. i replaced the spring with a piece of copper pipe the same size.

the mod is to replace the resistor not the spring though. Or are you saying you did both?

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[crxjarred]

i replaced bolth and didnt have a problem just tighten down the screw to hold it

I just replaced the resistor. It seems a little snappier but it could also be in my head. Starts quicker like mentioned, once again not a huge difference but deffinately noticable. It was free besides the gas I used to drive and get the bolt still a mod under $1. I cant do a good ride test where I live so i'm hoping to test it out friday or the weekend. I'm bring my resistor with me incase I run into any problems. Knocking would be my biggest fear, doubt it will happen though.

[uchi]

i wana get away from the atv specific plug and maybe jump into something thats a little more available to me. i find that every time i need a plug i need to wait almost a week for it to come in so i usually grab a few. but id like to be able to use something thats available locally that works just aswell. what are my options? 03 400

and this seems like a fairly simple thing to do. you gotta remember one thing. each small modification by itself might not make a difference. but you get 4 or 5 small modification and you combine the total power and then you start to see results. :)

[ae13291]

the only other place that has plugs in stock are dirtbike and atv shops. i order my plug from kragen, 6.99 for ngk iradium

[Snipe]

RMATV has them for $1.99 but there not the exact same plug as the one posted above but a NGK plug

Neat mod will have to try it let us know on the timing key advanced if it effects it at all or anything.

[dalejiw25]

Alrighty then...... What good is a monster coil if you leave the resistor in ????

Actually, if anything, this "mod" would reduce spark power. The resistor actually creates heat and if anything makes the spark hotter.

I think all of you should have never messed with it because it's there for a reason. Way to go jerry rig your coil. I think it's mainly in your heads. I have done that before, thinking something helped when it didn't.

[BEAVER.989]

Originally posted by DMC-4OOEX
Way to go jerry rig your coil. I think it's mainly in your heads.

You sure like to stir the pot, don't you? :D

Originally posted by BEAVER.989
You sure like to stir the pot, don't you? :D

hell yeahz:p

But in all honesty, that's my opinion. All these people just went and hacked apart their coil to take out a resistor which HELPS make a hotter spark, one of the reasons its in there, all because they think it will add .01 horsepower.

The only reason it probably starts faster is because the spark has less to travel through so it gets to the plug faster, but it doesn't make more power.

[Snipe]

This mod dont really add a huge performance increase nothing you could feel im sure on a dyno you might see something but as far as feeling it no. One thing getting a hotter spark out of the bike will do is burn more fuel giving yes some more power but also help with running rich (to some point).

It wont fix your problem totally if your running to rich but it will help. Also it makes the bike easier to start to me its like installing the 42 pilot, it makes for a easier start that is worth it to me. Took me all about 4min to do this mod and the it was free most everyone has a steal bolt laying around somewhere.

[400ex07]

How is it "hacked" ? It can go back in just as easy as it comes out. I did it and it does start easier and faster, but I did not feel any power increase.

[ae13291]

Originally posted by 400ex07
How is it "hacked" ? It can go back in just as easy as it comes out. I did it and it does start easier and faster, but I did not feel any power increase.

that red resister you removed absorbs some of the energy b4 it goes to the spark plug, now that you put a direct contact bolt or copper, etc.. it takes the current directly to the spark plug and makes for a faster spark.

Originally posted by ae13291
that red resister you removed absorbs some of the energy b4 it goes to the spark plug, now that you put a direct contact bolt or copper, etc.. it takes the current directly to the spark plug and makes for a faster spark.

Exactly, I couldn't have said it any better.

But I would still much rather take the hotter, stronger spark then have it start quicker, IMHO.

[400ex07]

DMC-4OOEX Exactly, I couldn't have said it any better. But I would still much rather take the hotter, stronger spark then have it start quicker, IMHO.

you are saying that the resistor amplifies the spark. wouldn't that make it an amplifier and not a resistor?

I think the resistor makes a longer less intense spark and taking it out will create a shorter more intense spark.

[ae13291]

it is a resister, not a capacitor! it will only absorb some energy to a certain point, there is different rated resisters that absorb more energy then others. i have had my resister out for some time now, and i have not had problems, it is your choice to do it, nobody is forcing you, if people had problems they would respond negatively about it.

[Snipe]

Exactly removing the resistor actually gives you a stronger hotter spark than having it in there,

So if you want a stronger hotter spark your arquing the wrong side of removal lol

Resistance generates heat, which a resistor in a ignition system helps generate a hotter spark.

[aDviSol2y]

After reading all of this, I decided to do a little research on this matter. Below is a link to a web site I found.

http://www.powerarc.com/sparkplug.htm

Scroll down and you will find frequently asked Questions. Here is one!

Q: Why should I use a resistor spark plugs & spark plug wires?

A: "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

You must use resistor spark plugs & wires in any vehicle that uses electronic ignitions or on-board computer systems to monitor or control engine performance. This is because resistor spark plugs & wires reduce (EMI) electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, or whenever recommended by the manufacturer.

In fact, using a non-resistor plug or low resistance spiral wound spark plug wire in most applications may actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels, abnormal combustion and probable damage to the ignition and/or ignition coil.


I personaly do not like the sound of the last paragraph! I am pretty sure that resistor is there for a reason.

[aDviSol2y]

Check this site out also. It explains even more.

http://www.motorcycleproject.com/motorcycle/text/plugwiretech.html

Originally posted by aDviSol2y
After reading all of this, I decided to do a little research on this matter. Below is a link to a web site I found.

http://www.powerarc.com/sparkplug.htm

Scroll down and you will find frequently asked Questions. Here is one!

Q: Why should I use a resistor spark plugs & spark plug wires?

A: "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

You must use resistor spark plugs & wires in any vehicle that uses electronic ignitions or on-board computer systems to monitor or control engine performance. This is because resistor spark plugs & wires reduce (EMI) electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, or whenever recommended by the manufacturer.

In fact, using a non-resistor plug or low resistance spiral wound spark plug wire in most applications may actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels, abnormal combustion and probable damage to the ignition and/or ignition coil.


I personaly do not like the sound of the last paragraph! I am pretty sure that resistor is there for a reason.

I told you guys. The resistor is there for a reason. If anything it improves performance.

[dankbud42o]

sounded like a nice mod...i was thinking the same thing, the resistor has to be there for a reason...and the previous posts above explain it...thanks for the tip but i think ill leave my resistor in.

[Snipe]

hahaha a KO on the research man I give you mad props for that.

[racer 557]

Originally posted by BigRed44
I'm still not sold on this mod. Does it help cold starts at all? What are the real advantages of doing it besides faster start?? Seems pointless to me.

i would say it prob helps in gncc becasuse you have to start with motor off so this helps i would say

[aDviSol2y]

Originally posted by racer 557
i would say it prob helps in gncc becasuse you have to start with motor off so this helps i would say


So you would you would risk potentially have all these problems with your motor to have 1/4 to a 1/2 second faster start?