Spark plug model number discrepancy

so the service manual mentions the NGK spark plug model as CR9EH-9 (and same with a website for motorcycle parts i use) but the NGK website is showing CR8EH-9 (or CR8EHIX-9 for iridium)

so is it the CR9 or CR8 ???

also, the manual states the maintenance interval for spark plugs to be replaced every 12,000km (8,000mi) which i think is a bit of an overkill, how long do you guys go between changing spark plugs?

i have put 30,000km (18,000mi) on the bike since last time i changed the spark plugs with no issues or hesitation all the way up to the redline, she seems very happy and healthy. i'm planning on changing them soon anyway, just wanted to know whats the general consensus on spark plug intervals

Seems like they are both right. This is from the owner's manual:

[image: plugs.jpg]

The RC79 uses iridium plugs. IMR9D-9H (NGK). They will last for well over 50,000km.

I’m not suggesting that you use the RC79 spec plugs in your bike, but an iridium plug might be better. Less faffing about with plug changes.

12 minutes ago, VFR78

I’m not suggesting that you use the RC79 spec plugs in your bike, but an iridium plug might be better. Less faffing about with plug changes.

i do have iridium plugs in the bike right now (10 years old and 30,000km on them) and the bike still pulls and sings very strongly all the way to 12,000rpm consistently