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By Presto
#54374
I guess one reason spark plug sand blaster type cleaners have disappeared – and to the best of my knowledge they have disappeared from garages – is that engines now run far cleaner than they did in our youth, and plugs don’t need cleaning like they used to. As jefrs says, in our cars plugs cover anything up to 100,000 without changing or cleaning. Why they seem to fail so easily as some folk are finding in their Bullets is a bit of a mystery.
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By PeteF
#54377
I think you would need a very severe leak indeed at the exhaust manifold to have any effect whatsoever on the combustion.
By jefrs
#54380
I did have a severe leak at the head to pipe. This is something like the fifth seal ring in there and I've finally got it shut up. I suspect the original indian pipe had the same problem crushing its cement biscuit seal because the note from the front is very much quieter now. Imo the combustion ran rich because the iridium plug fouled and started missing. The two conspired to produce soft soot in the exhaust pipe, the port and on the rim of the plug. Why the iridium fouled in the first place is a bit of a misery but other folks have had problems with this self same plug; conclusion unsuitable plug. I'll know better when I've got some miles on the new standard plug, there's a little too much black ice for my liking at the moment.

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