Topic: I am a dumbass

[Keith]

I was having problems with NGK plugs, so I switched to ND hotU plugs, following Hondaman’s advice. Started right up, and noticed smoother idle, so was excited to take her out for a run. Cruising the Taconic  Parkway (for you New Yorkers) running fine until I come to a hill, and the engine bogs terribly! WTF. I get home, check the basics.....fine. THEN I notice something blue sticking out of my air box. I had torn off a piece of t-shirt material and saturated it with mint oil to keep mice away. I had placed it on the engine over the clutch cover. I forgot it was there and never removed it, and it got sucked into the air box. @&$!. Removed it, and went for a spin.....ahhhhhhh back to normal!! Now I can say the ND plugs are far superior to NGK!

[Bankerdanny]

LOL, at least it was an easy fix that didn't involve stripping the fresh paint off a gas tank when you let it fall on the ground. Don't ask how I know.

[Scott S]

 What's the ND plug number? Same for 550 and 750?

[Keith]

X24ES-U. I don't know if the 550 uses the  same plug.

[ekpent]

 Maybe made for some interesting smelling exaust    I have a bar of Irish Spring soap under my riding lawn mower engine where mice like to crawl up into the shroud and build nests.  Some people swear by dryer sheets or whatever they are also.

[HondaMan]

The 500/550 uses X22ES-U.
I use this one in heavy city traffic in my 750, too. It's a bit too hot for 80 MPH interstate, though, on the 750.
I've also used the X24ES-U for my 500 (and recommend it for the 550) for long interstate rides, too.

Compared to the NGK D8ES-L (this is the correct CB750 NGK plug, almost unobtainium today, heatrange approximately like an imaginary D7.5EA plug), the X24ES-U (and the 27) has a thinner tip and more extended electrode, putting it directly into the swirl stream during the compression stroke. This lights off a slightly longer burn by not disturbing the pattern quite as much.

A disclaimer: If you have hemi'd the head of your 750 (like mine), there isn't much noticeable difference between the D8ES-L and X24ES-U performance, though, as the swirl pattern is not so pronounced anymore.