Iridium spark plugs?

**Bassmatt** · 14th September 2015, 15:31

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.

**neels** · 14th September 2015, 15:46

12k sounds more like standard spark plug replacement interval.

The iridium plugs in my merc are supposedly good for 100k, mind you there are 12 of the fuckers so you wouldn't want to be doing it too often.

**speedpro** · 14th September 2015, 15:50

My Toyota Blade has them. Replacement interval is 100,000Km. Good job as it is a mission to get to the back set.

**Bassmatt** · 14th September 2015, 16:48

Originally Posted by neels

12k sounds more like standard spark plug replacement interval.

The iridium plugs in my merc are supposedly good for 100k, mind you there are 12 of the fuckers so you wouldn't want to be doing it too often.

Thank god they aren't standard plugs, they'd want them replaced once a month.
I'm seeing 100000 ks mentioned alot online but ois all to do with cars. I suppose with bikes revving higher they will wear quicker. My last bike had them, pretty sure replacement interval was 40000ks.

**Katman** · 14th September 2015, 16:53

Originally Posted by Bassmatt

Thank god they aren't standard plugs, they'd want them replaced once a month.
I'm seeing 100000 ks mentioned alot online but ois all to do with cars. I suppose with bikes revving higher they will wear quicker. My last bike had them, pretty sure replacement interval was 40000ks.

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.

You should certainly be able to get 40,000 kms out of iridium plugs in a motorcycle though.

**caspernz** · 14th September 2015, 17:47

Originally Posted by Bassmatt

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.

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.

**Hitcher** · 14th September 2015, 18:09

The biggest risk with fitting iridium spark plugs are enthusiastic mechanics who replace them at the same intervals as standard plugs.

**jellywrestler** · 14th September 2015, 18:12

Originally Posted by Hitcher

The biggest risk with fitting iridium spark plugs are enthusiastic mechanics who replace them at the same intervals as standard plugs.

and them seizing in as they have been left a long time...

**Blackbird** · 14th September 2015, 18:24

Same distance recommendation for my Street Triple and Blackbird - probably lots of ass-covering by manufacturers. However, the "guru" Blackbird parts supplier in the UK told me there was no need to change them below 40k. Changed them at this interval and they looked visually perfect.

**caspernz** · 14th September 2015, 18:43

Ha, well whaddayaknow? Checked my Busa manual and the last service invoice, and yup 12,000 km change interval for plugs. Oh well, $26 a pop isn't cheap but then neither is owning a bike overall...

Different story for my cars though, standard has a short change interval and iridium runs much longer...just soooo boring to drive a car though innit?

**Trade_nancy** · 14th September 2015, 19:08

No 1 son has a Honda VTR1000 - service manual stipulates Iridium plug and a replace at 18,000km. We just replaced them at 43,000km and they were still OK - but showing signs of age...it was their time.

**AllanB** · 14th September 2015, 19:24

Standard plugs in the Hornet 900 with 24,000 km change intervals. They came out looking sweet at 24 too.

Suzukis aye ...........

**nzspokes** · 14th September 2015, 19:59

Originally Posted by caspernz

Ha, well whaddayaknow? Checked my Busa manual and the last service invoice, and yup 12,000 km change interval for plugs. Oh well, $26 a pop isn't cheap but then neither is owning a bike overall...

Different story for my cars though, standard has a short change interval and iridium runs much longer...just soooo boring to drive a car though innit?

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.

**jellywrestler** · 14th September 2015, 20:07

Originally Posted by Trade_nancy

No 1 son has a Honda VTR1000 - service manual stipulates Iridium plug and a replace at 18,000km. We just replaced them at 43,000km and they were still OK - but showing signs of age...it was their time.

so just how do you know they're OK? a lot of people think a plug is fine when hooked up to sparkplug outside the motor and it sparks, reality is can the naked eye tell the difference between a good and a not so good spark and of course, once in service the conditions turbulance etc inside a motor is a bit different from outside in thin air.

**Trade_nancy** · 14th September 2015, 20:39

Originally Posted by jellywrestler

so just how do you know they're OK? a lot of people think a plug is fine when hooked up to sparkplug outside the motor and it sparks, reality is can the naked eye tell the difference between a good and a not so good spark and of course, once in service the conditions turbulance etc inside a motor is a bit different from outside in thin air.

I don't. We didn't. That's why they were out and new ones in. Agree with you...