Were they gapped correctly when new? They should have been but, hey things happen. I would re-gap them if that's all that's wrong
and see how they go. I guess the only way the gap will increase is with spark erosion but what could cause accelerated wear? Excessive
spark pressure? Seems unlikely to me. I suppose if the engine is running weak the plug temperature could rise and perhaps cause excessive burning of the
electrodes which would be observable but, just guessing here.
I may, just for the hell of it, replace them at next service in about 4K miles
Which iridium plugs do you know are recommended for the Twin Cam?
I, so far, haven't been able to source any.
I use Denso IU24A in my 2012 R1200GSA, but you need a thin 16mm spark plug tool.
Interesting, i will look into them
