spark plugs

[Daranello]

I know that this subject is getting old for many of you. However I do not think that Bubba's question was understood properly.

I think that Bubba was asking about changing his stock CR9EB's with the dual electrode CR9EK's.

I put in the CR10EK's because that is what Ulmer recomended. However I have always been curious why we go one step "colder" in the dual electrode plug. Why wouldn't the dual electrode CR9EK be a better choice?

hmmmm interesting question

 

[Randy J Beyer]

All motors make the most horsepower with the coldest plug heat range that can burn the availble gas and air in a voluminous efficient manner !

In the case of yamaha motor's they have found that the CR10EKs work better than the CR9EKs.

Its not the dual electrode but the colder heat range
that makes the motor more crisp at most throttle settings.

An example where the plug is not better is at a very low idle or say a factory stock setting !

Sometimes when you go to a colder plug you also
need to increase idle speed !

Gains are so small that not all Dyno's will confirm these results !

 

[Blue Dave]

Thanks for the reply Randy.

Let me start off by saying that I am not trying to be argumentative and I do not want to beat this subject to death, I am simply curious and want to learn.

That having been said, now I am curious why Yamaha did not put in the colder CR10EB's.

I would suspect that Yamaha chose the single electrode "B" type plug over the dual electrode "K" type plug for cost savings reasons.

Therefore if the "10" heat range is in fact better than the "9", then why not a CR10EB? Perhaps more prone to cold fouling?

On a related note, I went to www.ngk.com and found that I could buy the CR10EK's for $6.18 each! However the shipping on a small order probably makes it about a wash compared to what others are charging.

Thanks again guys for all the great help that I have received so far on this site.

 

[Randy J Beyer]

Thanks for the reply Randy.

Let me start off by saying that I am not trying to be argumentative and I do not want to beat this subject to death, I am simply curious and want to learn.

That having been said, now I am curious why Yamaha did not put in the colder CR10EB's.

I would suspect that Yamaha chose the single electrode "B" type plug over the dual electrode "K" type plug for cost savings reasons.

Therefore if the "10" heat range is in fact better than the "9", then why not a CR10EB? Perhaps more prone to cold fouling?

On a related note, I went to www.ngk.com and found that I could buy the CR10EK's for $6.18 each! However the shipping on a small order probably makes it about a wash compared to what others are charging.

Thanks again guys for all the great help that I have received so far on this site.

Iam curious too why each manufacture does some of things they do !

Yamaha like all the rest, takes a very conservative appoach to motor's and makes sure that there is room for varibles such as heat range,
temp range, fuels, air, ect.....

to make sure that these sleds will perform in whole erray of climates, weather conditions, hot or cold ect......

They dont engineer anything on the edge!

Thats good for us sledheads that we get a chance from
time to time take things to the limit!

The reason I belive they dont install the CR10EB plugs is
that all there reserach and development has told them to
use the single electrode 9's and that it is the correct plug
for all things considered!

Cost savings is considered but they do intend to develope
these sleds to run smooth and trouble free for many miles.

People on this forum have stated they run better which in most cases they do !

In the eyes of yamaha they are not better !

And in some cases yes they are harder starting in cold weather ! Have not heard of alot of fouling !

I too have learned alot on this site ! Great that we get a chance to comment on some of the issues !