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

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 

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.