The Honda book lists NGK CR9EH-9 or Denso U27FER-9 sparkplugs for my 2001 VFR800FI. The Denso at least is a copper plug.
Bike Bandit lists NGK and Denso iridium plugs for more than twice the money.
Will I really see longer plug life or any other benefit from the iridium plug? I'm tempted to stay with stock, not so much because I'm cheap but because it is the factory recommendation.
What do the assembled experts think? Thanks in advance.
Here's a real expert talking about ignition systems:
Go Iridium. And yes you can gap them, just be careful.
I know about iridium from my Celica. It is a high compression engine with a redline of 7800 rpm. I changed the plugs at 100,000 miles and at that time saw no difference in performance. I think the motorcycle takes more abuse and does not last that long, but this made a fan out of me.
I put iridium plugs in 42,000 trouble free miles ago and they still look great
Here's an idea.
Change you plugs as often as you do your valve checks, its when I remove the plugs anyways so iridium is the go for me.
In the manual it says plugs 12000KM and valve check 24000KM and repeat that cycle but from what I've read not many follow the valve check to the km specified.
The iridium plugs would be ok with that and the labour you don't do can go into ride time.
btw, I have a car that has a 180,000 Km Iridium plug change schedule. Only change them a few months ago. Not bad on a car made last century. Plugs would have had more life in them if I hadn't broke some in the removal.
Great. Thanks to all for your advice!