irregular sparkplug discoloration

The last two plugs I have pulled have burned unevenly in the ceramic core, where one side ends up much darker than the other. Any idea what causes this?

Re: irregular sparkplug discoloration

I recall reading that the pattern is just an indication of which parts of the plug and combustion chamber get hotter than other parts, and it changes with conditions.

The turbulent fuel mixture swirls around before and after the mix ignites .. exactly how it swirls, which part ignites first and how it spreads depends on a lot of factors.. the shape of the combustion chamber, the spark plug's position.. the aim of the transfer ports have something to do with it.

Re: irregular sparkplug discoloration

So is it symptomatic of any sort of problem, or just something odd that happens?

Re: irregular sparkplug discoloration

there are so few absolutes with 2-stroke engines that i hesitate to sat it's not symptomatic of a problem. But in the absence of any other 'symptom' i think it can be safely ignored.

Re: irregular sparkplug discoloration

Mike Scouty McScoutington /

is your bike running ok now sara? how is your compression? when i had a plug come out uneven like that i had a bad gasket and that was why my plug temp was uneven.

Re: irregular sparkplug discoloration

My bike is almost not running at all right now. It stopped right after the BBQ. I have crazy high starting compression and what feels like bad running compression. I sort of wanted to get new gaskets anyway, and if you think the plug is symptomatic of them being bad maybe I actually will.

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