I was reading elseware that some guys are putting the cr9ek plugs in instead of the cr9eh9 stock plugs. Has anyone tried this? I dont want to try something that is unproven.

 

You can run the CR9E plug family. The EK plug will have acouple threads that stick past the head into the chamber and get all gummy...so turning the plug out can do damage to the threads. I've found HP gains using the EK plug in other bikes, but haven't triedin the CBR.

The CR9EIX is an iridium plug, and is a safe alternate to the crazy honda part number with longer life than "copper" plugs. I have that in my cbr now.

Check out sparkplugs.com if you don't have a local source....they are a forum sponsor. I've bought from them before and been pleased.

 

are you using a CR9EIX or CR9EHIX-9?

 

just the cr9eix. That plug has full threads.

the CR9EHIX-9 gives a threaded portion with partial thread, as the oem plug has.

Just an FYI. Iridium (and Platinum)plugs are about longer life than copper/nickle plugs...don't expect HP gains out of them.