Recently I did some tuneup on my bike and among other things thought what the heck let me make the plugs gap larger. The reason being it supposed to produce larger and stronger spark, helping better the combustion. The manual calls for 0.8mm gap and I made each to be over 1mm (approx 1.1mm). The bike starts and runs perfectly. I like it!
The plugs were visually in great shape (less than 2k on them).
So this is just an idea. Does it quality for being called a "mod"? LOL
Before you celebrate keep an eye on your mileage. I never thought of increasing gap to make the spark hotter. I doubt that's how it works. The larger the gap, the more voltage needed from the ignition coil to jump the gap. Since you're just beyond the gap limit, you may find that it will start missing soon.
Got over 70 miles on that setup so far, never missing a bit. I agree the voltage needs to be higher to jump the larger gap. Do you think there a chance I fry the spark coils?
The spark plug voltage is between 20k and 60k volts according to Wikipedia. So the larger gap requires the coils to produce higher voltage, say 25k vs. 20k volts (I have no idea on actual numbers for GS voltage though, just illustrating the point). So far judging by my riding experience that voltage is still within limits of GS500 electrical design.
From Wikipedia - http://en.wikipedia.org/wiki/Spark_plug
narrow-gap risk: spark might be too weak/small to ignite fuel;
narrow-gap benefit: plug always fires on each cycle;
wide-gap risk: plug might not fire, or miss at high speeds;
wide-gap benefit: spark is strong for a clean burn.
I suspect this may work ono the damn virago rear cyl I have.
I went to resistor plugs, doubt you'd fry the coil, but yes you may not light up but I'd think @ low speed more than high speed.
Cool.
Buddha.
Revved it up to 9k RPM a handful of times. No problem as far as I feel it.
No, a wider gap won't fry the coils. Either the coils will supply enough voltage to jump the gaps or they won't, but it won't load them more. Once the spark occurs the gap's resistance drops from very high to almost zero, so coils are made to be essentially shorted-out thousands of times per minute.
I just check that my gaps are in spec then I don't think about them until I take them out and the electrodes show some wear, then I replace them.
Quote from: reminor on June 26, 2009, 01:51:53 PM
Revved it up to 9k RPM a handful of times. No problem as far as I feel it.
Keep it at 9k under load and let us know how it works. (seriously)
Even if according to the specs you're in the 20k to 60k window where everything works, you might still find a high RPM miss.
A coil has to recharge between firings.
A coil has no problem keeping up with demand at lower RPMs. At high rpms the time to recharge is reduced. If it can't recharge fully it can't deliver a full powered spark. Eventually any system will get to a point where it is uncapable of meeting your demand (20-60k) since the recharge time is approaching 0. Adding to the demand by making a bigger spark plug gap just makes that point happen sooner.
I'm curious to see if a stock GS500 system is capable of supporting the higher demand of a big gap at high rpms under load.
Coils do not need to re charge between firings. You're thinking CDI, that actually does need to charge and it does that on the primary side of the coil - AKA in the black box. We have I believe TCI. TCI's send a signal based on the inductive pick up.
Drag cars run the hi power ignition to fire off a 60,000 volt spark as opposed to a 20,000 spark. They also can run a higher current at that 60K. The spark will fire even when there is crap on the plug really and that extra amperage on the spark side is to burn the crap sitting on the plug. If there is any.
Load or not does not may any difference - very very very very little difference in electricity. Characterstics that change with load are all carburetion related.
9K is 9K is 9K for electrical system. 9k is idle = pilot jet - 1/8 throttle, 9K in 1st is quarter throttle 2nd is 3/8th, 3rd is 1/2. 4th is 5/8th. 5th is 3/4 and 6th is impossible. AKA carburetion.
What is load vs electrical correlation - 9K @ loat = you're running 90 mph. There is bound to be tons of jolts here and there and that can cause loose and broken connections types. Very small possibility. but a possiblity none the less.
Cool.
Buddha.
Huh?
Buddha, read this link...especially the part in transisterised ignitions (it's TSI, not TCI) about extensively long recharging.
http://www.mclarenelectronics.com/Products/All/App_Act_Ign.asp (http://www.mclarenelectronics.com/Products/All/App_Act_Ign.asp)
There used to be more stuff written here but I removed it because I came across sounding like a d..k and that's not what I wanted.
You dont get something for nothing and a gain somewhere in a system means a loss elsewhere. A bigger gap requires a bigger spark which requires more energy and bigger volts, in turn this will increase the loading on the coils, upshot is the coil will run hotter and the life of the insulation on the copper wire will be shortened. A bigger spark will also wear out the electrode and shorten the life of the plug quicker. Ultimately the gap gets so big the coil struggles to produce enough energy to actualy generate a spark.
I will ask the obvious question, if it was so advantagous and so simple why havent Suzuki or the plug makers done this from the word go?
Personaly and with respect, I think you are suffering from the placebo effect and will guess that within a few hundred, maybe 1k miles at tops your bike will start missing at high revs.
When I put in new plugs I was just over the speck and I couldn't get the particular cylinder to fire. From my limited understanding, you'd prob be ok if it runs now. You should keep an eye on it because as the plug ages the gap increases, and you might be end up with to high of a gap in the middle of nowhere.
OK you do know this is a GS500 he's got right ?
OK just making sure.
Cool.
Buddha.
You might find a high RPM full throttle misfire. But I doubt it. A bigger spark is better. With the crap mixture preparation of a carb it might help.
why does everyone say it will take more volts to jump the gap and to many volts will fry the coils. the voltage will be what the battery puts out. it takes current to jump the gap which is amps. you got pressure=volts current=amps and load=resistance. so all that power flowing through the coils and wires is current not volts. volts should be close to your source voltage. That is why fuses are rated in amps and not volts you can run more voltage through a fuse 12,14,18,20.... but voltage wont do much harm to components unless stated but high current will fry stuff. so a bigger gap will require more current cause the resistance of the gap got higher so current goes up voltage is still the same and the coils will get hot. that is why we have specs for the gap cause the coils can only take so much current.
Hey.......put me down for a few bottles of whatever it is your drinking :thumb:
Nope.
Not even close.
You should read up on it.
This is quite brief, but start here:
http://en.wikipedia.org/wiki/Ignition_coil
Quote from: mach1 on June 26, 2009, 09:31:42 PM
why does everyone say it will take more volts to jump the gap and to many volts will fry the coils. the voltage will be what the battery puts out. it takes current to jump the gap which is amps. you got pressure=volts current=amps and load=resistance. so all that power flowing through the coils and wires is current not volts. volts should be close to your source voltage. That is why fuses are rated in amps and not volts you can run more voltage through a fuse 12,14,18,20.... but voltage wont do much harm to components unless stated but high current will fry stuff. so a bigger gap will require more current cause the resistance of the gap got higher so current goes up voltage is still the same and the coils will get hot. that is why we have specs for the gap cause the coils can only take so much current.
Hi all,
Sledge is right.
A bigger gap may work "well" now but the penalty is that this will cause your coils to work extra hard, shortening their lives.
Sorry you and mach1 don't like the answer, but that's how it works.
Put your gaps back the way they are supposed to be.
There are reasons for these things from the factory.
Good luck,
Trwhouse
EDIT-
MY APOLOGIES!!!!!
I meant MACH 1.
Sledge slipped in his post before mine hit, and I mixed up names because of it.
Original (with strikeout) below.
I respectfully disagree that what
Sledge MACH 1 presented showed an understanding of how ignition coils work.
I won't deny that that running a larger gap might make a coil fail earlier.
Quote from: Trwhouse on June 28, 2009, 11:44:12 AM
Hi all,
Sledge is right.
A bigger gap may work "well" now but the penalty is that this will cause your coils to work extra hard, shortening their lives.
Sorry you and mach1 don't like the answer, but that's how it works.
Put your gaps back the way they are supposed to be.
There are reasons for these things from the factory.
Good luck,
Trwhouse
I'm with sledge on this. It's high voltage that allows the spark to occur, and it's thousands of times greater than the battery voltage. The ignition coil is connected and disconnected to and from the battery over and over by the ignition box, or contact breaker points on a mechanical ignition. When the connection opens, the magnetic field around the coil collapses. The collapsing field generates thousands of volts to the plug by electromagnetic induction. Even if a coil can produce a billion amps, if the voltage isn't high enough at that moment no spark will occur. In this case once the gap becomes large enough to reach the limit of the coil's voltage during induction, the engine will start missing, and it would happen first at high rpm.
If you'd like to experience electromagnetic induction for yourself, connect an ignition coil to a 12V battery. Hold the leads, then disconnect one of them from the battery and feel the shock. Try it, you'll like it!
I know the ignition gives off high voltage trust me I have felt the shock many times but i also performed amp readings from the coil at school and thats what you see jumping the gap the voltage is just pushing it across. alot of people think thats incorrect including most mechanics but voltage is just pressure thats it. the high voltage pushes high current. the spark you see is electrons moving from one point to another. Im not wrong you can show me stuff on the wiki but that does not make it correct, I have read it in my electrical theory book and tested that theory at school. So go ahead widen the gap but you will need a stronger coil. my explorer they have an aftermarket coil so i can widen the gap, the gs does not have that aftermarket part.
Tard farm here we come....
The air gap in a spark plug can't exactly be modeled with a resistor like mach1 says. A lot of things just don't seem to add up. By your claim, the voltage across the electrodes is only ~12v.
While yes, when the arc occurs between the electrodes, there is current flowing as the air ionizes and the circuit is completed, but it's really the high voltage that is necessary to get it to ionize in the first place. And the strength of the air gap as the dielectric increases with the bigger gap, so a higher voltage is needed to start the arc.
http://wiki.answers.com/Q/Can_back_EMF_be_greater_than_battery_EMF
:police: :D Here for general knowledge :
http://auto.howstuffworks.com/ignition-system2.htm (http://auto.howstuffworks.com/ignition-system2.htm)
To the OP , if you want better spark buy iridium spark plugs,more expensive but last much longer
New coils are 80$ each 8)
This thread = fun.
:icon_rolleyes:
Inductance, capacatance, resistance. Watt's a matta; you no obey Ohm's law! You could be king faraday. :cool:
prs
I didn't expect my topic would spark (literally!) so much interest. :icon_lol:
The best test would be to disconnect one cylinder, revv-up the engine and see/hear. Then repeat the same with the other cylinder. If no missing occures then the gap mod is in fact working, though outside of the design specs for GS500.
The effects of a larger gap are unlikely to be obvious from the start and the method you suggest wont account for the long term degredation of the plugs.
To make an accurate comparison and avoid the placebo effect you would need to take two identical bikes, fit one with standard gap plugs as a control and another one with oversize gaps. Dyno, fuel consumption and emission test them both. Run them both for say....... 1k, assuming the bike with oversized plugs makes it! over similar conditions then repeat the tests and compare the differences.
Quote from: sledge on June 29, 2009, 01:29:46 PM
The effects of a larger gap are unlikely to be obvious from the start and the method you suggest wont account for the long term degredation of the plugs.
To make an accurate comparison and avoid the placebo effect you would need to take two identical bikes, fit one with standard gap plugs as a control and another one with oversize gaps. Dyno, fuel consumption and emission test them both. Run them both for say....... 1k, assuming the bike with oversized plugs makes it! over similar conditions then repeat the tests and compare the differences.
I was talking about the mod viability check, not about obtaining some scientific numbers on the performance differences. I have no time nor second GS500 to perform all that noncense.
If GS500 does not misfire or burn parts as a result of the mod, it means it is viable. By how much it improves the bike performance? Who knows.. Theoretically there
is a stronger spark, so there
is some performance improvement.
People do far crazier mods to their bikes. :icon_lol:
OK opening the gap causes increase in resistance. The spark may not jump at low revs. But once the voltage hits the jump point it should be fine. It will cause a drop in current, because V/R is current.
BTW the low voltage side of the coil is not 12 V from the battery, its 15-75 volts AC from the alternator. I cannot see it ever losing high speed. I believe low revs first will die. I would really not worry, we throw in resistor plugs in the things all the time. My virago runs better with resistor plugs than regular BS plugs.
Cool.
Buddha.
This thread is going so far, ahem, afield!
When the bike is running there is about 15 volts on line, DC. Everything on the bike runs on DC, after the rectifier. And sure, the spark is current, but it takes thousands of volts to make it begin, and that's why an engine with too large spark plug gaps will begin missing at some point. And it isn't so much the energy of one spark that determines if the coil can keep up, it's the increasing energy needed as rpms increase as there's less time between sparks, increasing coil and ignition module load, since the module controls the coils. The ignition module and coils are actually seeing a greater load of the larger plug gaps more often with increasing rpms.
And a hotter spark isn't always better. If that was the case, mechanical ignitions would work better than electronic ignition as mechanical ignition delivers full coil power to the plug every time as it can't regulate spark current. Electronic ignition does regulate spark current, delivering enough spark current for the engine load, but no more. That's why plugs last longer with electronic ignition over the old points and condenser, like I have in my old 77 XS 750 triple, with three sets of points.
So to summarize, all increasing the plug gap does on this bike is increase the load on the coils and ignition module. Sledge and I are correct. Argue with us at your peril. I'm not looking to pick fights on issues like this or anything else. I have an electonics degree and 27 years of experience. I'm here to shed light and disperse myths. Japanese engineers are smart on these issues. You don't see them playing with plug gaps, do you? They selected the ignition coils and module for your bike with the recommended gap for good reasons. If you can successfully outguess a team of Japanese electrical engineers you're a better man than me. It's all about covering the rpm limits of this engine with parts that are up to the job. They selected them. They left the specs alone for 20 years. What does that tell you? You can observe it or suffer the consequences.
Quote from: bill14224 on June 29, 2009, 05:28:44 PM
.... You don't see them playing with plug gaps, do you? They selected the ignition coils and module for your bike with the recommended gap for good reasons. If you can successfully outguess a team of Japanese electrical engineers you're a better man than me. It's all about covering the rpm limits of this engine with parts that are up to the job. They selected them. They left the specs alone for 20 years. What does that tell you? You can observe it or suffer the consequences.
That is all correct, however we all know that longevity/problem-free-product/budget considerations put a lot of strain on the designers. Companies (at least Japanese LOL) want to produce dependable long-lasting machines, but at times at the expense of performance (obviously except race-oriented ones). Nothing's wrong with that. They try to design machines performing well in a wide variety of situations. God bless them. GS500 is one example. Simple, dependable, archaic, cheap, unintimidating.
But we are exploring and tinkering with the design, often obtaining better-than-designed parameters. Examples? Igniton advancer. Smaller front sproket. Braided brake lines. Wider rear tire. Katana shock. Progressive springs. Rejetting. Etc, etc, etc. This board is choke full of those ideas. God bless it.
More spark is better, it's a fact. Otherwise some modern engines would not have two spark plugs per cylinder.
You see where I am driving to?
Peace.
P.S. I will ride with my enlarged spark gap, just to give you guys some feedback in a year or two. You stay as you are. Nothing's wrong with that. That's how the humans progress. Some go ahead and take risk. Some stay back and wait. Nothing's wrong with either. I've used somebody's experience countless times doing the mods others explored before me. I am thankful they took the chance (and the risk) to light my way.
Reminor - Yes I will await your observational postings.
Bill14224 - The jap companies have/had 2-3 phases.
In the 70's and 80's they were out to take over the world. They built solid machines that ran and ran and ran ... not extrordinarily grat in any respect but not too horrible in any other aspect. In that phase they were very hard to improve upon. They fixed their problems themselves. Example - early virago'/s starter problems. Gone in 1984. 81-83 bad, 84 on was great. Maxim's had transmission problems. Again second gen maxim fixed. List is endless.
Then came the "why aren't you buying more parts from us phase" The virago became the Vstar - yes not one of the problems was fixed, and many were made harder and worse. Virago of 84+ once in a while will eat a ignition box. The new Vstar - it still eats it, but its now encased in tar. Much harder to get out and fix. The oil change on a Virago is a 1/2 hour job. You ahve to remove the case guards to get the filter out. Vstar - that + removing the exhuast which is much much harder than a GS - think collector box under the motor and its shoved in there tight. Plus they added a few nice ones just to catch ones that are sleeping - rear spark plug - near impossible to not cross thread on the way in, and hard as heck to get a wrench on on the way out. Open shaft, that really really likes to rust. Once again, coat it with oil or it will look like the ... well forks.
Agreed GS is more form the first phase and we can only make small improvements - as opposed to huge en masse changes and I think this is worth trying out. especially on my damn virago.
Cool.
Buddha.
Here's my update after over 250 miles on the spark plugs with enlarged gap. I measured the gap and it is 1.05mm (stock is 0.8mm) on both plugs. Take a look at the picture. The plaugs had over 2k miles on them before the mod. I think they look good. The bike runs perfectly.
(http://i29.tinypic.com/2605ydf.jpg)
Well, I just had to put in my 2c....
Plug gaps are probably specified by Suzuki a little on the small side of the ideal, so that as they wear they don't get too big. It also would mean that people who don't check their plugs often enough aren't bad mouthing the bike for misfiring. So, if the spec is 0.8mm I guess the ideal gap is maybe 0.9 or 1.0. If you enlarge the gap a little and check it frequently I suggest you would probably have no problem, but I doubt you'd see any noticeable gain in performance.
As for the larger gap 'overloading' the coils, I call :bs:.
Yes, if the voltage is only JUST ENOUGH to get a spark and the gap is made larger you will need more voltage to get a spark. That does NOT mean the coil will magically produce more voltage. The coil can't 'know' how big the gap is and adjust its voltage accordingly. It just means that if the voltage it is already producing is not enough then you won't get a spark.
In fact, there is more than enough voltage for the normal gap, so if the gap is a little bigger it still works.
(Ducks behind sandbags and waits for incoming rain of used sparkplugs!)
Let him carry on with the exercise, no one said anything would happen short term.
There is an effect of larger plug gaps, I felt I should chime in. I remember a while ago when switching our old 1988 Honda Accord to splitfire plugs. It idled roughly and stumbled a little bit at low revs. Turns out the more exposed electrode actually advanced the timing a little bit which isn't detrimental at higher rpms since normal ecu's advance timing at higher rpms naturally but at lower rpms it can cause problems such as higher cylinder head temps and stumbling or even knocking. There is a slight delay between when the plug fires and creates a small fireball in the spark area to when that fireball spreads and ignites the fuel-air mixture. A larger gap does expose more mixture and even though it is not a hotter spark it is a larger fireball in the immediate spark plug area, and has the effect of advancing the timing, which possibly accounts for why the op feels there is a slight difference as advancing the timing manually can have an effect.
As to the long term effects I would later be concerned with misfiring later on down the line. You're probably not going to end up damaging the coils but there is a possibility, if there was a small manufacturing defect or damage in the coil's insulation repeated misfiring could end up burning through the weak spot in the coil's insulation and you end up with a coil that grounds to itself. A rare occurrence but a possibility nonetheless.
Just an FYI 101 on ignition to spark plug:
Ionization of the gap is the good start to begin the flame kernel development. And that requires a certain voltage level at a certain amperage level. The width of the gap, and the turbulence and pressures in the combustiion chamber greatly affect what those voltage and amperage values have to be; or what they need to be. The ignition coil has to be able to supply the required voltage at the needed amperage flow, as quickly as it can, once it has been triggered to do so. That is known as 'rise time'.
Once the ignition coil has produced and delivered that required voltage pressure and amperage flow to jump the gap across the plug electrodes, the spark commences. In other words, the ignition coil is triggered, the magnetic field collapses, the induction of high secondary voltage commences [voltage rising], and the gap is starting to tingle in anticipation [ionize] for what is coming real soon. When the spark actually completes the jump, the ionization is complete: we have a spark.
The width of the gap has its effects on the quality and the intensity [heat] of the flame kernel that develops as the spark is sizzling across the gap. A wider gap will require more voltage/amperage to make the spark actually happen, so that can be a good thing. If you can jump the gap, that means that you had to have some heat there to get it to happen.
I was reading the topic about fixing the cold blooded nature of a GS by increasing the valve gap and it got me thinking about this thread. I wonder whatever happened to that bike.
Hi reminor are you running low octane fuel in your bike or is the brown colour from your normal running .Could you post a better picture of the earth electrode a side on view would be nice.
HOLY CRAP ITS A ZOMBIE POST!
let it die... get iridiums good day sir!