Those are completely wrong. You will see a lot of places claiming other plugs to fit when they actually do not.

 

The man to the rescue - thanks for this super helpful.

 

Why change them to a non standard plug?


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Use oem ngk lmar9ej plugs only. There was a national back order on them before and I’m not sure if there still is. I found a vendor in California that had them. I live in Pittsburgh

 

CR9EIX are for 05-08 R1.

-09 and on NGK SILMAR9B9 would be the right iridium plugs..

 

I can verify that the irridium plugs cited above work fine. Specs are exactly the same as the non irridium stock plugs, including heat range. Only difference is irridium have only one ground electrode.

 

Yamaha engineers did the work to get the right plug for the r1 engine so just go by what they spec

 

Don’t use anything other than NGK LMAR9E-J

 

I can't say what's wrong or right.
I've run both stock and iridiums in the -07 and both worked fine, no difference in performance but the iridiums will (hopfully) last longer.

To be fair, i've never noticed the stock copper core plugs been worn out when changed at service..

As always, if in any doubt go by the book and you can't go wrong.

Just out of curiosity, beside the extra cost, are there any technical reason why -09 and on won't work with iridium plugs?