KX 100 Spark Plug

Hi Guys,

What spark plug should I run in my 1997 KX100? The manual recommends NGK R6252K - 105 . Should I use that?

Thanks and ATB


use a br8es or br9es

i use 2 dollar plugs from cycle gear (ngk) and they are great...be safe and do what the manual says

Br8es, been in all my 2 strokes since 1974.

use a br8es or br9es
Br8es, been in all my 2 strokes since 1974.

Thanks guys for the suggestions, I have looked the above spark plugs up and they are very cheap compared the the recommended ones! :thumbsup:

It will not effect performance or anything else if I use BR8ES?

Thanks and ATB!

Jimbob....if i understand the NGK nomenclature, the 105 portion of the number refers to the the spark plugs heat range (10.5). The BR9ES, BR9EG, BR9EV, BR9EIX are the next increment hotter (heat range 9) and the BR8ES, BR8EG, BR8EV are the next increment hotter (heat range 8).

With my daughter's '09 KX100, I ran the R6252K-105 plug since it is still the factory recommended. We ran it for trail riding with 32:1 pre-mix ratio (factory recommended) at about 8K altitude with stock jetting (45 pilot; 138 main) and we fouled out the plug about 3 hours into our first trail ride. I have since changed the jetting to 42 pilot and 135 main and went to a BR9EG. So far so good. I had read a lot of forum posts indicating the 105 plug was too cold and unless you are racing you will foul them out.

I would recommend you only move 1 heat range at a time and make sure you believe your jetting is about right (i knew that the factory stock jetting would likely be too rich at high altitude and sure enough it was).

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