Spark plugs

[Speedy1959]

Hi all,
I know what "the book" says about spark plug replacement intervals.
That seems a very short change interval.
Do you all replace yours as the book says or do you have your own regime.
When I originally owned Sophie I replaced at 30k miles.
She's now done 40k miles. I am doing a service on Saturday and wondered about plugs. She is running perfectly with no misfires or any other bad plug symptoms. I have a new set of NGK plugs in stock (NOT IRIDIUM).

My inclination is to change when I change the air filter.
What is your plug regime ?

[grog]

Over kill Speedy. Will easily last those miles again.

[GSXKING]

Just for your own peace of mind I recommend removing, checking and regapping if necessary, clean if there is any build up (unlikely as that seems) refit and do another 40,000 untroubled miles. 

I personally fitted iridium plugs as they were on special several years ago. I reckon they've been in the bike for 60,000k's and are still great. 

[Snapey]

My policy is if they break down then replace them.

[grog]

GSX sim story with iridium from me. Can of worms left closed. Whatever works for yourself i reckon.

[Sweaty]

She is running perfectly with no misfires or any other bad plug symptoms.

I think you have answered your own question with this quote Speedy 😉

[seth]

As every one else says if it's running well leave them alone
Just as a lifeline I thing the very short oil change service intervals is due to the lining in the barrels .
The rest of the motor can easily do double that mileage with no problems at all .

[northern]

Last week I was on dyno.

After fitting last year Yosh cams, I could not get power, engine should output. It turns out, HP filter needet to be replaced. First I drill HP filer throw and made external filer mode. Later, during winder, fabricate my steampunk fuel filter solution 
Now I finally get time to dyno tune my bike with enough fuel distribute...

After ~3 hours, tuner told me, what he get everything he can from this engine. And it was same 125HP on the wheel, like it was last year, with not enough fuel...
WTF! how it's possible?

Starting discussion with tuner and other specialist in the shop (among other services, they are dealing with race bikes), they point my attention, what iridium spark plugs what I have for last ~18000km, are very sensible for reach AFR, which I had after I fix my fuel distributive. Even if it give OK spark, carbonized plug could slightly affect ignition timing, which could easily steal ~10% of power.
This is approximately what I miss.

Regular NGK here in cost ~ 7.50€ (best price, someone even sell for 18€!!!) iridium cost 3€ more. Not much to spend on hobby. But for myself I deside to use now one regular sparks, but change them more often.

Which I did this week: set of CR8EK cost me less then 30€.
Maybe, I will manage to test run it on a dyno, using new and old plugs to compare, but not sure about this.
What I'm sure of - Saturday I'm planning to drag-racing. If my time will be better then last year, then it's 30€ well spend 

[Hooli]

I've got the third set of plugs in my 14. After 50k miles the bits outside the engine start to get too rusty for my liking so I change them.

[GSXKING]

@northern I'd like to try drug racing 

[froudy]

I fitted Iridium plugs at 13663 miles and finally changed them at 45374 miles..Some 31,700 miles later.
Never again as they had well and truly rusted and I was worried about snapping them off when I finally removed them..They were that fookin' tight!!!

[GSXKING]

They only need to be 40nm tight 

[northern]

They only need to be 40nm tight 

even less - 11

[grog]

A bit of coppercoat or never seize helps

[Horse]

 If you use lubricant make sure you adjust the torque value accordingly, if you don't decrease it you may or may not have an exciting time repairing a slightly bigger hole than you started with.

Have a good weekend,
Horse