Spark plug gap for NGK B8ES and its equivalents?

'79 KZ1000E-1. What's the proper gap? I know there is a range of "acceptable" gaps. What's the difference between gapping at the smaller acceptable limit versus the upper limit? How does this effect combustion characteristics?

Also, which is the better plug between these two?

1.) NGK B8ES

OR

2.) ND24ES/U

A tighter ignition gap may tend to squish the spark kernel and a wider one may be almost at the limit to produce a useable spark. I like the in between gap.

I've used both and I did not notice any performance change in my 82 GPZ1100 B2, but I have the stock ignition system
and can't comment or different coils or other ignition parts.

I am running the stock CDI ignition system to answer your question. What is the number of the right spark plug gap? What's the range, so that I know where to set the gap in the middle of the two numbers?

Unless someone pipes in otherwise........

I like the B8ES, with out of the package gap for both my 650B2 and 1000E1.

I usually change them out at the start of every season.

It is always nice to fire up the old girls with new plugs. For the 12.00 that it costs it is a minor cost for piece of mind as well as you can throw the old ones in the tool box under the seat if you need a spare.

I do not know what the gap range is. I have been told by other users that the factory gap is fine with the B8ES.

Someone might pipe in and tell you to use B7ES, but being a hotter plug, I thought it was only to be used if carbon fouling was an issue and even then you are better off doing the WG coil mod / adjusting your carbs to get around that problem.

If someone knows the gap measurements please let us know. Other than that factory is cool enough for me.

KRB)

.028-.032 is specified. Out of the box is usually right at about .030. No difference will be noticable whithin that range. No difference between the NGK or ND, but I use NGK.

Indexing spark plugs is a way to get some better combustion.

Indexing Spark plugs? I just clicked on the link..Why didn't I know this before? Thanks! So correct me if I am wrong about placement.. You want the exposed flame kernel facing the center of the combustion chamber OR facing the intake valve or exhaust valve?

Facing towards center of the combustion chamber, slightly towards the exhaust side IIRC.

Correction below.

Just found this post on kz650info.com about indexing plugs and it says near the end: "Did we forget something? Oh yeah, what do you index the open electrode towards, Well, it depends on what kind of bike you have. On most japanese bikes you just face that index toward the intake valve."