Iridium plugs

Steve97 · Post by **Steve97** » Sat Jul 09, 2011 5:09 pm

Have just changed plugs to iridium (expensive) and cant help noticing a distinct "detonation" when shes running, is this normal ? its far more pronounced than the normal NGKs i took out , every thing else is fine no farting banging, runs like a dream, seems to pull stronger and accelerate faster, and i thought it was ok before the change ! just a bit worried that holes will be burned in pistons, or some other such problem,
Thanks fellas

Steve

Animal · Post by **Animal** » Sat Jul 09, 2011 5:53 pm

I think you'll find that iridium plugs are a standard fitment for the Firestorm.
Its what the 'i' in dpr9eix stands for.
Nothing to worry about there.

Steve97 · Post by **Steve97** » Sun Jul 10, 2011 5:35 pm

Not sure about that Animal, both the original owners manual and the Haynes comic state that the standard plug is NGK DPR9EVX maybe the iridium plug is standard on later models ? mine is a 97, cant put my finger on it mate but something is just not right !

Furrybiker · Post by **Furrybiker** » Sun Jul 10, 2011 9:25 pm

Steve97 wrote:Not sure about that Animal, both the original owners manual and the Haynes comic state that the standard plug is NGK DPR9EVX maybe the iridium plug is standard on later models ? mine is a 97, cant put my finger on it mate but something is just not right !

Workshop manual says the same..............

tony.mon · Post by **tony.mon** » Sun Jul 10, 2011 9:36 pm

Steve97 wrote:Have just changed plugs to iridium (expensive) and cant help noticing a distinct "detonation" when shes running, is this normal ? its far more pronounced than the normal NGKs i took out , every thing else is fine no farting banging, runs like a dream, seems to pull stronger and accelerate faster, and i thought it was ok before the change ! just a bit worried that holes will be burned in pistons, or some other such problem,
Thanks fellas

Steve

If it runs stronger and accelerates faster, just be grateful

If it burns holes in pistons you can fit high comps!

But as the ignition timing is unaltered it won't do that.
Check the plug caps; it's easy to crack the 90 elbow inside the rubber housing when pulling them off.

Animal · Post by **Animal** » Sun Jul 10, 2011 10:10 pm

Must admit dont normally bother with manuals for that information, normally go straight to the manufacturer. Check out the link.

http://www.ngkpartfinder.co.uk/mc_searc ... ngine=1000

Post by **sirch345** » Mon Jul 11, 2011 4:06 pm

Steve, just to put your mind at rest, I've been using iridium plugs for the last 18,000 miles with no problems yet,

Chris.

Steve97 · Post by **Steve97** » Mon Jul 11, 2011 5:40 pm

Thanks for your help lads, will stick with it for a while, just cant believe the diference!! faster, accelerates harder,
Vibrates a little more, its a bit like having the choke on just a touch, anyway its running really well so will just get on with it.
Oh and one other thing, bet you cant explain this one, changing the plugs has stopped the clutch rattle !!!
Dont you just love this bike !!!

Thanks again
Steve

tony.mon · Post by **tony.mon** » Mon Jul 11, 2011 7:04 pm

Steve97 wrote:, bet you cant explain this one, changing the plugs has stopped the clutch rattle !!!
Dont you just love this bike !!!

Thanks again
Steve

I'll have a go....

Any petrol four-stroke engine runs unevenly, because the crankshaft speeds up as the piston goes down after ignition has occurred.
It then slows down because of internal friction and load until the next ignition/power stroke.
So the lumpiness of a single is because the piston accelerates the crankshaft only once in every to complete crankshaft rotations, and the crankshaft slows down a little during the rest of the cycle.

So this means that the crankshaft is not spinning at a constant rate, speeding up and slowing down as fast as the engine is rotating- up to 10,000 times each minute.

The clutch has a little play where the engagement squares on each clutch plate (or the splined teeth for the metal ones) engage on the clutch basket or centre splines.

That's what rattles.
There can't be no tolerance as in order to operate the clutch plates have to slide sideways with as little friction as possible.

Plugs spark at very specific points in each revolution, and normal plugs aren't quite as exact as Iridium ones, due to a wider area at which the spark can occur, meaning that the spark is more variable. By fractions of a degree, probably, but even so....

By fitting new iridium plugs, the ignition happens in a much more controlled way, at a more exact point in each rotation of the crank. (every rotation, as there's a wasted spark system).
This means less variation in the exact number of degrees before top dead centre the ignition spark (and therefore power pulse) occurs.

less variation means less difference each time round for the power pulse,, and so less rattle.

You can see this for yourself if you use an oscilloscope, and watch the timing marks dancing around in the strobe light.

Easy.......

Steve97 · Post by **Steve97** » Wed Jul 13, 2011 2:56 pm

I think we.ll leave it there then Tony.........

darkember · Post by **darkember** » Sun Jul 17, 2011 1:32 pm

Would I be correct in thinking if both plugs look like the one below then the fueling is pretty well spot on?? Light brown tan.

benny hedges · Post by **benny hedges** » Sun Jul 17, 2011 2:44 pm

looks BIT on the rich side to me that bud.
light tan is more like the colour of a rich tea biscuit
that looks more like a dark chocolate digestive!
whats your air filter like?

btw iridium plugs dont last forever.... change them every 5k at least for best performance/
the one in the pic looks past its best.

darkember · Post by **darkember** » Sun Jul 17, 2011 3:42 pm

Just ordered 2 Iridiums & a new filter from wemoto as mine does look a little grubby. Thanks

benny hedges · Post by **benny hedges** » Sun Jul 17, 2011 4:50 pm

well, taking my own advice, realised ive done over 14k on my plugs

so searched my garage for new ones as i had 2 pairs of brand newies somewhere.
i could only find one of the 4

so i had to order some new ones - very cheap & free delivery from here

so at that price, no excuse. if yours are past their best, get them changed!

sorry to urinate on your chips darkember but you couldve had 2 delivered for the price of 1 at wemoto and still saved a few quid lol

darkember · Post by **darkember** » Sun Jul 17, 2011 7:09 pm

benny hedges wrote:well, taking my own advice, realised ive done over 14k on my plugs so searched my garage for new ones as i had 2 pairs of brand newies somewhere.
i could only find one of the 4

so i had to order some new ones - very cheap & free delivery from here

so at that price, no excuse. if yours are past their best, get them changed!

sorry to urinate on your chips darkember but you couldve had 2 delivered for the price of 1 at wemoto and still saved a few quid lol

I do agree benny, however, for components like that I like to go to a supplier I know & have used before, the extra few quid is worth it. Take a look at the following links you may have seen them before.

http://curezone.com/forums/am.asp?i=1063782
http://www.ngk-sparkplugs.jp/english/te ... index.html

VTR1000.ORG

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