On my 1994 Suzuki Katana 600, it is way overdue for valve adjustment. Unfortunately I'm unable to get the valve cover off. I have what appear to be all the bolts removed (there's 14 of them across 3 different types, plus 4 more for the oil cooler lines). I suspect it's just stuck in place from old age. I've been tapping around the edges with a rubber mallet, but no luck. I'm afraid I'm going to need a more aggressive method...
The parts diagram shows 14 fasteners. Qty. 8, 2, and 4 of #5, #6, and #8 respsectively.
After that you should be able to separate the cover from the cylinder head. If it won't come off with gentle tapping, try prying with a paint scraper or similar thin bladed tool. You'll want to be careful not to scratch the surface of the cylinder head. If you have a plastic scraper, that would be better to start with since the plastic will not scratch the Aluminum of the head and cover.