I have a 1984 200es and I run what THe book tells me two a NGK 7es or 7 something, im not sure about that i just know it is 7.
I want to run a cooler plug to keep my temperature down. What plug do you recamend and WILL THIS DECREASE PERFORMACE OR AIR FUEL MIXTURE BURN.

 

The "cooler" heat range of a spark plug would to be go UP in number, hence the next "cooler" plug would be a B8ES, then a B9ES. The cooler plugs are safer to run typically. My experience has shown that there really isn't much difference in jetting by switching from one heat range to a cooler heat range. I.E. a B8ES to a B9ES...

 

<a href="http://www.ngksparkplugs.com/Pages/locator.html">ngk plug locator</a>
some plug numbers go up, others go down...depends on manufacturer.

------------------
Steve Small, '00 400ex
'00 Trail Boss for the wife.
Impuls90 for the boys.
<a href="mailto:extreme400ex@home.com">EXtreme E-mail</a>



[This message has been edited by EXtreme- (edited 01-10-2000).]

 

Yeah, watch Champion..they are hotter as the number goes up..but who would run a champion in there bike!? I would run a dpr9z or 9 with the same letters are your current plug in hot weather, and a 8 in cold.
Joe

 

I know that NGK plugs are cooler when the numbers go up, and hotter down. The engine will run slightly hotter with a hotter plug, but will burn more carbon off the plug and have a better spark. As for the colder plug, you will have a little cooler running engine.

 

So would you say that running a NGK7es year round is ok. IF i run a cooler plug won't it burn not as good. I run my motor a little on the rich side just to keep temp don't