What plug came with the sled? I think that the number "9" is the heat range of the plug. I don't remember if a lower number is a lower or higher heat, I think that it is hotter. Ask your a dealer what plug goes in that machine, and I would stick with NGK my dad's 1998 700 RMK went over 5000 miles with the original set of plugs.
Snowmachining is not a thing to do - its a way of life
I'm pretty sure the slead came with 9's I would suggest staying with NGK BR9EYA's
the manufactures spent hundreds of thousands of dollars designing their machine to run well I doubt they over looked the spark plug.
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