E3 Spark Plugs

[EatACookie]

Hey guys, I just got some E3 spark plugs for my bike. but for some reason they dont fit inside the rubber housing cap (I think its called the boot correct me if im wrong)

I looked at the stock NGK spark plug and the E3 spark plug and I noticed that the stock spark plug has a threaded top while the E3 has a nipple looking top. Look below at what im talking about





Whats the difference between the two?
How do I fit my E3 spark plug into the Rubber boot?
Do I have to take off the nipple looking thing first? (I noticed a thread covered by the nipple contraption.

And yes, I got the correct E3 spark plugs to replace the stock one. according to the cross reference chart for changing spark plugs

Thanks for the help guys!

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UPDATE!

found out what I needed to know and how to take that terminal off. took me a while to find it but i did!

[codajastal]

I was going to say the top unscrews and you can put it on the other but I see you already did

[noworries]

And what's the other hard rubber sleeve that I found on the left-hand plug of a new GS500 but not on the right and could never get back over the plug again? Anyone seen this/know how?