Denso Iridium Plugs.

[Julio A.]

Before trying it with the R65, I installed one on my XR200 Dirt bike.  

The Difference when using this plug is ridiculously significant.
Engine idles much more smoother, the thing can be ridden as soon as it is started. Unlike before that there was a 5 minute warp-up period. There is a also a noticeable increase in acceleration.

The company claims that it also increases mileage and improves gas efficiency; I'll wait for my next full tank before commenting on that.

But there is a downside. A Single Iridium Plug costs as much as three regular plugs. Now imagine investing on those with 4 cylinder bike.

I'm not endorsing them or anything. I'm just too surprised. I got more performance from this single spark plug than when I upgraded to an open exhaust kit.  

[Bob_Roller]

Another member here, Semper Gumby uses them and has had a similar experience with them .

The ignition system on our bikes, the wasted spark system is pretty tough on spark plugs, as they fire twice as many times for the same usage .

[nhmaf]

I may give those a try with my next tune up!  I used to use the Bosch Platinums in my 88 R100RT which were also quite pricey, but did make a difference in smoother idle and fuel mileage.

[Semper Gumby]

Two thumbs up for fine wire plugs.

I use the NGK BPR7EIX Iriduim.  The cost factor is overridden by the fact that they have been on the bike for more than 30,000 miles.  The tips just don't wear out!!   8-)

[Ed Miller]

Do you still use the 5K ohm resister spark plug caps?

[Semper Gumby]

Do you still use the 5K ohm resister spark plug caps?

Nope. I use NGK 0 ohm LZFW caps.  The NGK resistor plugs have about 4300 ohms of resistance built in so I figured that was enough.

[Motu]

For a waste spark ignition you will need double iridium - that is iridium on the earth electrode as well.

[Semper Gumby]

For a waste spark ignition you will need double iridium - that is iridium on the earth electrode as well.

Not really. When the gap opens up you just close the gap by bending the electrode towards the center iridium tip.  They just go and go.  heck I may get 100,000 miles out of them at this rate....  

[Julio A.]

Resistors of the plug caps? I've heard of capacitors but why would anyone like to reduce voltage going to the spark plug?

I'm pretty sure the splitfire caps I use don't have them.

[Bob_Roller]

Most gasoline engines use resistor type spark plugs, it's usually the first letter in the part number .

There are even spark plug wires that are resistor type, the center conductor looks like a thread with carbon on them, not copper .

The airhead BMW bikes, have non-resistor type spark plugs, but the spark plug cap has the 5k ohm resistance .

I believe the resistance value actually produces a stronger but shorter arc at the spark plug .

[Motu]

Not really. When the gap opens up you just close the gap by bending the electrode towards the center iridium tip.  They just go and go.  heck I may get 100,000 miles out of them at this rate....  

You would be better off swapping sides every 6 months to get even wear on the earth electrode - but why waste the money on fancy plugs if you are going to wear out the plain steel earth electrode? The whole point of iridium is that it will last longer.

[Motu]

I believe the resistance value actually produces a stronger but shorter arc at the spark plug .

Yes,if you study ignition on a scope you will find resistance doesn't effect spark voltage but spark duration.

[Barry]

Adding extra resistance to the ignition lead/plug/cap:-

Doesn't normally reduce spark voltage - because normally the plug sparks at a much lower voltage than the coil is capable of producing.

Does increase spark duration - because added resistance limits current so it takes longer for the energy to dissipate in the spark. Generally thought to be a good thing.

Does reduce total spark energy slightly - because some energy is absorbed by the added resistance. Can't be otherwise according to ohms law. Obviously not a good thing but probably insignificant unless the added resistance is way too high.


It's interesting to compare the old points ignition with the later electronic ignition system which has coils that are capable of twice the spark energy of the points coils.

And yet the recommended plug gap was left the same at .024" - .028" The reason may have been to increase the spark duration.

[Semper Gumby]

The stock BMW caps have about 1000 ohms of resistance in 'em.

One of the reasons I have either a) resistor plugs or b) resistor caps is for Noise Reduction.  The ignition system is very noisy.  On my 1969 BSA Firebird, above about 5000 rpms the Garmin GPS can't see the satellites anymore and becomes a boat anchor.

The reason I have Iridium NGK fine wire plugs on my BMW R65 is for ease of starting in Winter!  It just starts better.  I have never had a noise problem on the R65 with the GPS but I have had trouble starting in cold weather.  The NGK Iridiums make the bike easier to start -- very important in the company parking lot after four days of sitting out in the open in less than 0'C weather.

In fact everything I have done to this bike: Omega Ignition, Omega Alternator, 10W40 oil in the fall, Iridium plugs, PC680 battery with the right trickle charger, perfectly balanced and set up carbs is done to achieve one goal -- a successful start in the company parking lot at 2AM at an outside temperature of 20'F after 4 days out in the open, so I can go home.   8-)

[trolle]

In fact everything I have done to this bike: Omega Ignition, Omega Alternator, 10W40 oil in the fall, Iridium plugs, PC680 battery with the right trickle charger, perfectly balanced and set up carbs is done to achieve one goal -- a successful start in the company parking lot at 2AM at an outside temperature of 20'F after 4 days out in the open, so I can go home. Cool
 

A dedicated man indeed!

greetings from a sunny and drying north