Hello New member here. a couple Q's

Hello my name is Dj and i have been browsing around the forum since i got my 82 seca XJ550 about a month ago. Thought i would finally introduce myself and my bike. I traded my 1999 Buick century for the bike. i use to own a 2003 Yamaha YZF600r sportbike for my first road bike. sold that about a year ago and have regretted it ever since. So now ive finally been back on the road on two wheels. heres a few pics of my xj.

this is right when i got her


and now




also i do have a few questions. #1) i got a headlight cowl with my bike. not attached. i went to go and attach it and i could not find a place to mount it? I thought i knew where it went but if i put it there it wouldnt fit right on the bike? idk i tried flipping the mounts around and still wrong? maybe its to a 650 or 750 seca fairing? #2) after riding for while my idle likes to hang high around 2500rpms. but if i pull the brake in it will lower them down and if i let go they will rise again? also kind of sputters from stop. plug 4 looks blacker than the rest also. any ideas. i put seafoam through and it helped a lot but still does it.