Worst Spark Plugs Ever Made?

Classic Goldwings

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Supporting Member
Dec 16, 2009
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North Carolina, USA
My Bike Models
My candidate is Splifires.

These plugs were basically a heavily marketed "gimmick" product that was popular in the 90s. Splitfire made outlandish claims about fuel mileage and emissions benefits and eventually got zapped by the FTC for making deceptive claims.

I've used just about every brand of plug ever made. Most work OK. These days I generally use NGK, Denso, Bosch or Champion with good results. But Splitfire is the only brand of plug I've ever seen that self-disintegrated in a carefully ridden, perfectly tuned bike (GL1000). The center electrode came loose and was rattling around inside the cylinder.

"Indexing" or "end-gapping" plugs is actually a good idea. I routinely do that. But. Splitfire overstated the benefit ...then manufactured a crappy product.

These eventually became scarce after the FTC ruling. But, you can still find a few of them if you look hard My advice: avoid them.


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