For some reason we decided to have a look at the sparkplugs which are the original ones on the 2010 cb1100.
Something vitally importand on this bike is to clean any debris around the sparkplugs so as to prevent sand, small rocks and other hard things falling into the cylinder and " make themselves at home there " .
We pried some small loose rocks out of the cavity, blew around the sparkplugs before starting to loosen them, some loose grit came flying out with several blows in the small plastic tube, and also before the sparkplugs were completely removed some more loose stuff was "blown away", the second lot surprised me but there it is, easy to overlook this debris.
and here are the plugs after 70.000 Km, the gap is 1 mm., the spec is 0.8 to 0,9 mm and i think i have gapped them before around 25.000 Km.
To me it seems fine for another 30.000 at least;
and the tools i used to get them out and i used the smalles amount of 90w gear oil on the threads which helped a lot when putting them back in the engine, we"ll see if that was a good idea some time later;
So we think that removing them has some risk included because of the debris our bikes are prone to collect and it is easy to forget to blow the plugs clean before removing them, hope this helps.