View Full Version : Denso Iridium Spark Plug Fit

11-18-2012, 01:29 PM
So I purchased a Denso (5731) IXU01-27 Iridium Racing Spark Plug. I see the recommendations for this plug everywhere so I decided to give it a shot. My only issue is that it doesn't fit! I put the old plug in various times to be sure I had placement right and it wasn't just me being a tard. The Denso plug will screw in a turn or so and lock up.

Am I doing something wrong, can anybody please shed some light on my situation?


11-18-2012, 01:51 PM
Take the new plug and see if you can place its threads into the old plugs threads

If they match then you are cross threading the plug into the engine.

11-18-2012, 03:20 PM
Thanks Loki, I'll take the tank off and try it again.

11-18-2012, 03:21 PM
Be careful not to strip the thread in your head...

12-01-2012, 03:30 PM
I got it! For whatever reason there was slightly more resistance when screwing it in opposed to the stock plug.

That being said, the performance boost that this plug provides is phenomenal. I'll putting an iridium plug in all of my bikes!

12-03-2012, 10:14 PM
Why I recommend it - lol -