Spark plugs - sooty

[rgh0]

For a Twincam it is hard to get a plug that runs hot enough at idle to not soot up but does not run to hot when the engine is being used hard.

[elanman999]

My dyno man blames the ethanol in the fuel for the plugs and exhaust being sooty.

When I last ran carbs, ten years ago, 7’s used to foul occasionally and 6’s were good. Either would wet if one pumped the throttle too much on cold startup.
Cheers
John.