Iridium spark plugs?

[Motu]

Most motorcycles (before the advent of cam position sensors) use a wasted spark ignition system which means that the spark plug fires twice as often as it would in a car.

Hillman Hunter? Waste spark was the norm in cars '90's, 2000's, mostly COP now. If you are using plat or iridium with waste spark you need double plat or iridium - one plug jumps from centre to earth, the other earth to centre, so that one that jumps from the earth electrode is going to wear faster. If they are single fine wire that is why the shorter life - pointless, go double.

[Oakie]

Have read somewhere that a standard plug gives more power, proven on a dyno. Has a better flame path or something. Was ages ago I read it. Iridium last longer but is not as powerful.

Not sure how true this was but there you go.

Just changed iridiums for standard plugs two weeks ago and the bike is going noticably better than at any time in the last 18 months.

[Erelyes]

I've anecdotally heard that coppers give a better spark (or are more forgiving of a weak igniter) than iridiums or platinums as well. Better conductivity or some such.

[Black Knight]

You cant "read" em like a standard plug

[Shaun Harris]

Who uses these and what is your bikes manufacturerz recommendations on replacement intervals.
My new Suzuki apparently requires new ones every 12000 kms!
Sounds fucken ridiculous to me but happy to be told otherwise.

That is simple bullshit, to aid there dealer network with sales, same as all brands

[speedpro]

Shaun is on to it.
Much of the rest of the replies are to be taken with a grain of salt. Iridium plugs have lower voltage requirements for a spark given the finer tips. This will result in a more regular spark even in adverse conditions such as a lean spot in the maps or very high speed and a drop in voltage due to ignition limitations. Some have a fine tip on the earth strap as well. The ceramic will colour up just like any other plug ceramic. Given the durability of the materials used in the spark gap I have no problem believing they would be good for 100,000km in a car and possibly some lesser distance in a bike.
New plugs that replace worn plugs could easily improve performance, even plain standard plugs versus flash Iridium or other fine wire types. Personally I have dynoed a bike with fresh fuel, plugs, filter, etc, and at the end I fitted new plugs and gained 2 horsepower, 95hp to 97hp. This was a repeatable gain and the "old" plugs looked fine and there was no indication of a problem with them apart from the gain with the new plugs.

[PistonBlown]

When I fitted them on my bike was told minimum of 45k between changes (standard sparks are 15k). So 3 times the life of the standard ones is probably a rough guide.

[husaberg]

The idea of the super expensive plugs being in a low tuned road bike over a predetermined milage is mainly based on meeting emissions standards.
But if performance has suffered replace them they are not really that expensive.

[LBD]

Spark plug life and electrode erosion is directly related to how often it fire... Cruise around at 2000rpm and your plugs will last 4 times longer than if you were screaming around at 8000 rpm....

[neels]

Spark plug life and electrode erosion is directly related to how often it fire... Cruise around at 2000rpm and your plugs will last 4 times longer than if you were screaming around at 8000 rpm....

Assuming you're not in the same gear of course, otherwise they'll fire the same number of times and you'll just get there in 1/4 of the time.

[Laava]

When I fitted iridium plugs, I noticed that it no longer seems to be revving as high. I used to be doing 4500rpm at 100kmh but now, thanks to iridium plugs, it has dropped down to 3800rpm.

FYI I had them fitted professionally at Ichiban Moto

[Laava]

Check your manual and you'll probably find 12,000 is the interval for standard plugs, with the iridium ones being due around the 100,000 km mark or so.

No, he is right, mine is the same and further to that, they are only available from suzuki.

[Big Dog]

When I fitted iridium plugs, I noticed that it no longer seems to be revving as high. I used to be doing 4500rpm at 100kmh but now, thanks to iridium plugs, it has dropped down to 3800rpm.

FYI I had them fitted professionally at Ichiban Moto

I might be wrong but I always thought revs were a fixed ratio of speed unless the gearing ratio changed?
E.g the piston does the same number of cycles to the same number of tyre rotations aiming the same gearing ratio?

A drop off 700rpm would be more akin to going up one more gear or equivalent sprocket change.

Sent via tapatalk.

[nzspokes]

I might be wrong but I always thought revs were a fixed ratio of speed unless the gearing ratio changed?
E.g the piston does the same number of cycles to the same number of tyre rotations aiming the same gearing ratio?

A drop off 700rpm would be more akin to going up one more gear or equivalent sprocket change.

Sent via tapatalk.

Ichiban Moto is never wrong.

[Laava]

What NZspokes said.