spark plug NGK B9ES instead of B8ES

[gert du prez]

Hi,

the guy in the store sold me B9ES instead of B8ES with the additional info that this is certainly ok...

is it ?

and what would the effect be for my beloved GS 1100 GL ?

 

[rustybronco]

B9ES is a colder heat range plug. more likely to foul out.
http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp?nav=31000&country=US

 

[bigbill808]

yes it is perfectly fine. the only difference between the plugs is its temperature range. some times depending on where you live and the climate you have to run either a hotter or colder heat range plug. i have two sets of plugs, one for summer and one for winter. running the correct heat range plug will allow for easier starts and smoother acceleration. hope this helps.

 

[cowboyup3371]

According to the NGK site, it doesn't show up as fitting your bike:

http://www.ngk.com/results_fitment.asp?pid=B9ES

But i'm not that smart about it either

 

[GSexpress]

The 9's will run OK, but you live in a cool climate and if you weren't having any problems with pinging or running hot, the 9's cold cause less efficient combustion. You could have a drop in fuel mileage and some plug fouling and harder starting in winter. Higher levels of alcohol in the fuel can increase those tendancies. The 8's should be just as readily available as the 9's. The shop just wanted to move what was on the shelf. More for their bennifit than yours.

 

[1948man]

Page 35 of the Owner's Manual says B7,B8,or B9 depending on conditions with B8 being standard.

 

[Steve]

If you were racing on the track pretty much exclusively, go ahead and use the 7s.

If you use your bike on the street, use the 8s.

By the way, "colder" and "hotter" plugs don't make the engine run colder or hotter.
It's a matter of how well they sink the heat that is generated by combustion.

.

 

[Suzuki_Don]

If you check out Cowboys NGK website you will see the only bikes on that list are ALL 2-STROKES. No wonder the dealer could not get rid of them.

 

[gert du prez]

So, in conclusion I understand:

Don't do it and stick with what was decided for the bike...right ?

 

[Steve]

So, in conclusion I understand:

Don't do it and stick with what was decided for the bike...right ?

You catch on quickly, son. :clap: :clap:

.

 

[bwringer]

So, in conclusion I understand:

Don't do it and stick with what was decided for the bike...right ?

Right.

But if these are the only plugs you can find in all of Belgium, it won't hurt anything to ride with them.

Honestly, you'd probably never notice a difference.

But it just wouldn't be right, you know? And I suspect that would bother you. It would bother me, too.

 

[trippivot]

I see bad spark plug info on this thread.

I see bad spark plug info on this thread.

B9ES is a fantastic spark plug for highway riding and racing in all temperatures !!!

I have a set of B10 EG I use in the summer heat when racing.

technically speaking you want the coldest plug that will just reach a temp of 550 ~600F that is how hot it needs to be to clean themselves of all contaminates. The biggest problem is most guys do not have the patience to let the bike warm up fully with colder plugs installed. Most start riding in the wind right from the start which only makes things worse and keeps the machine in a pre warm up state - due to the efficiency of the air cooling effect from the fins - The symptom is it runs like crap until a proper amount of heat is built up in the piston crown...

that is unless you carbs are still out of whack in that case 7's 8's or even 6's will not help you running condition..

 

[gert du prez]

I can answer myself now on my own question...
After several months out of 'business' (coil relay modification, valve adjustment but shims smaller than 1.85 mm - other post) I pressed the START button and the bike fired right up. Never happened before...excellent...

but, at 3,000 rpm with the B9ES plugs, it started to make loud tight 'CLACK-sounds'. Quickly replaced the new B9ES with old B8ES and tested again...the sound was gone...

 

[Bakes]

By the way, "colder" and "hotter" plugs don't make the engine run colder or hotter.
It's a matter of how well they sync the heat that is generated by combustion.

Yeah, what Steve said!

From NGK's website:
The spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called ?Thermal Performance?, and is determined by the heat range selected.

The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.
Heat rating and heat flow path of NGK Spark Plugs

Some basic structural factors affecting the heat range of a spark plug are:

• <LI class=copyC2 type=disc>Surface area and/or length of the insulator nose <LI class=copyC2 type=disc>Thermal conductivity of the insulator, center electrode, etc. <LI class=copyC2 type=disc>Structure of the center electrode such as a copper core, etc.
• Relative position of the insulator tip to the end of the shell (projection)

The major structural difference affecting the heat rating is the length of the insulator nose. A hot type spark plug has a longer insulator nose. The insulator nose of a hotter spark plug has a longer distance between the firing tip of the insulator, and the point where insulator meets the metal shell. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. The insulator nose of a hotter spark plug also has a greater surface area that is exposed to more of the ignited gases and is easily heated to higher temperatures. A colder spark plug functions in an opposite manner.
The heat range must be carefully selected for proper spark plug thermal performance. If the heat range is not optimal, then serious trouble can be the result. The optimal firing end temperature is approximately between 500?C (932?F) and 800?C (1472?F). The two most common causes of spark plug problems are carbon fouling (< 450?C) and overheating (> 800?C).


In summary Gert - 7s will work in your bike. 8s are "optimal", for what that's worth, but 7s wont hurt anything, nor will 9s.

Hope this helps.

 

[koolaid_kid]

If you check out Cowboys NGK website you will see the only bikes on that list are ALL 2-STROKES. No wonder the dealer could not get rid of them.

Woohoo! My GPz750 is a 2-STROKE! No wonder it runs like a bat out of hades!
Just for informational purposes, my 81 KZ750 used B8-ES plugs. My 83 GPz750 uses B9-ES. It is almost the same engine; the GPz has higher compression, hotter cams and bigger carbs. But the core engine components are interchangeable. So it is an example of when you would go to a colder plug. Personally, I run the plug specified by the manufacturer. They do thousands of hours of testing and evalution to determine the correct range. Trust their work.

 

[gert du prez]

Ok,
so that would also mean that the difference I think I experienced in the engine between the B8ES and the B9ES are purely 'in my head' and not in the cylinders (if that expression exists in English) ?

 

[GSexpress]

What Bakes didn't include is that ambient conditions also effect combustion temps. cooler or hotter climates and cooler or hotter burning fuels change the conditions. That's why the manufacturer has more than 1 heat range listed for use. In our case those recomendation were before the common use of alcohol mixed and unleaded fuels. The fuels we have now don't burn as hot. and therefore a colder plug may be too cold, particularly in a colder climate as the cooler air also causes cooler combustion temps.

If it starts to get a little hard to start when cold and has a hesitation or stumble when you whack the throttle open, then the 9's are too cold for your riding conditions. It may take some miles for that to show up as it builds up some fouling deposits.