Topic: Spark plug condition?

[M_Stone76?]

Hello, first off, not sure if I’m posting in the right place
I need one advice on new spark plug condition after a ride ( a pretty hard 10 mile ride)
They plugs are new ngk D8EA gapped to 0.026.
The electrode is ash grey on the top, porcelain is clean white and the outside is a dark copper color.
This is the same for all 4

[BenelliSEI]

What bike are they in? For a good plug reading, you need to bet running hard, shut down and pull them. Not idle through town, into your neighborhood and home, them pull. Regardless, I’d say you are running way too lean. Will be interested to hear what others say.

[M_Stone76?]

Cb750 SOHC 76’
Isn’t it very bad to pull plugs while the engine is hot?

[willbird]

Cb750 SOHC 76’
Isn’t it very bad to pull plugs while the engine is hot?

IMHO they do not have the be pulled with the engine hot, the point is that the engine must be shut off quickly after a pull so idling and such does not alter the reading. That said I have pulled plugs 1 and 4 without any bad things happening with the engine hot. I am not enough of a devotee to pull 2 and 3 on a hot engine LOL.

Bill

[grcamna2]

The gasoline out here in Ca. is very poor quality and it's also difficult to get a nice,visual,accurate plug reading,considering..
I was wondering what your new spark plugs color look like during standard riding after a few hundred miles ?

I find the NGK D8EA plugs run a little hotter than the Denso X24ES-U.
The tip of the porcelain on the NGK is a bit 'squared-off' shape compared to the tapered porcelain on the tips of the Denso X24ES-U plugs.
The edges of the porcelain tip of the center electrode post is sensitive to heat and they tend to flare-out a bit on the NGK's,and I prefer running the Denso plugs.
The main reason is this Ca. gasoline seems to make my engine run hot on the Interstate at high speeds,plus the Ethanol gasoline seems to degrade quickly and if I don't use the bike for over a week,it will pre-ignition,which cooks the tip of the plugs.
I have helped this poor quality fuel a bit by mixing a 30/70 ratio of NV. 91 octane Ethanol-free/Ca. 87oct Regular Ethanol gasoline into every tank-full,which keeps the stuff from causing too much pre-ignition.
The bike sits outside in the sun and the tank is black,which I'm sure doesn't help to keep this gasoline from degrading sooner.

[BenelliSEI]

Cb750 SOHC 76’
Isn’t it very bad to pull plugs while the engine is hot?

IMHO they do not have the be pulled with the engine hot, the point is that the engine must be shut off quickly after a pull so idling and such does not alter the reading. That said I have pulled plugs 1 and 4 without any bad things happening with the engine hot. I am not enough of a devotee to pull 2 and 3 on a hot engine LOL.

Bill

+1. As long as you chop it off without a lot of idling, cold is fine.

[HondaMan]

Ten miles may not be a long enough test run for plug color in a 750, if it is carb'd close to correct. They might, at best, just be starting to show a color then, in my experience. If they are getting dark already in that distance, the mix is rich in the RPM range that was run.

That said: a lot of 750 riders would kill to have plugs that clean! Many of them run rich with today's fuels because they burn much slower than the 1970s fuels did. Today, running on Regular is about the same burn rate as 1970s premium.

[Honda Hansel]

Hi
Are you running stock air-box or pod filters

Running a bit rich will not be bad thing
That will help cool the combustion temp in the cylinder
I my self like it on the rich side just to help cool the combustion a bit
and eliminates detonation on a hot day (yes we do get hot days in Alberta )

Honda Hansel