Plug gap bridged

[chuckie]

Went to ride on sunday. Bike didn't feel right. Not the usual oomph, anyhow  I headed back home and started pulling plugs. left side # 4 cylinder plug was bridged with a sliver of what appeared to be carbon, not sure. I cleaned it and rotated it to another hole. Plugs all otherwise looked good no fouling at all. My question is what could be the cause of this plug bridging like that.
Thanks Chuckie

[Gryphon Rider]

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[Pete]

If it only happens once, ignore it.
Piece of stray carbon broke off and bridged the plug.

Happens a lot on 2 stroke engines, seldom on a 4 stroke engine.

Did you leave the choke on longer that usually while at idle?
And then push the choke off and take off immediately?

This can rarely be traced to a rich condition on a 4 stroke engine.

I have had it happen 1 time on a 1997 Std in 9,000 miles.