The 12R uses a unique (and expensive) sparkplug. The NGK CR9EK-PA. I'm going to guess it goes something like this... The "R" stands for "resistor". The "9" is it's heat range. The "EK" indicates that it has two side electrodes that stop at the side of the center electrode, instead of the "conventional" single side electrode that goes over the end of the center electrode. Here's what makes the plugs so "pricey", the "PA" stands for "platinum".
I ran the CR9EK in my 7R and really didn't get any more wear out of them when compared to the conventional plugs. Ah, but they were NOT the platinum version. I'd guess one of the reasons KHI chose the PA plugs is that changing the plugs on the 12R is not quite as easy as it is on their other sportbikes. The unique frame design and the Kleen Air plumbing (if your's is still on the bike) can make accessing the plugs a tad frustrating (but not impossible using the plug tool in your tool bag).
I believe specs say to change the plugs at 12K miles (could be 15K). I inspected mine at 6K, 10K, 13K and replaced them at 16K. I saved them because all four of them were "paper bag" brown with no build up or signs of the the center electrode burning off (would happen with the non-PA plugs in my 7R). I feel that I could have got many more thousands of miles of them. In other words, the CR9EK-PA are very durable plugs and should last for well over 12K miles.
If you wish to inspect them and you feel that the need to be cleaned, you might want to figure out why they need cleaning. Is the bike running too rich? Is there an oily build up on the plugs? If there is, you better be more concerned over what's causing first. Anyway, if you clean them, just about any carb, brake or contact cleaner should do the trick. I just use lacquer thinner because I have a 55 gallon drum of it at work.
Gapping the plugs can be a little trickier. They do come "pre-gapped" in the box (or when they installed them at the factory). I'll probably get flamed for this, but unless something looks out of the ordanary with the gap (which I've never seen), I don't bother with checking the gap on EK plugs. I used to with my 7R and found that they were always correct out of the box and the gap never changed while in the bike. That's just how I feel about it. That doesn't make it right.
Makes sense. I am just cautious, because my baby doesn't start up as fast as she used to. She sounds much more hoarse now then than she did before. I can tell you this though. Cleaning your airfilter makes a big difference. It idles much stronger now. Went up like 150-200rpm. I get this big whoooonnngggghhhhh sound above 5000rpm. I'll hold off until later, unless it starts sounding like an old chevy or something.