I presume this is a 750 we are talking about?
I can't help much as I'm a 650 user but the sprocket question is common enough, undo the two small bolts on either side of the sprocket centre and then rotate the holding washer until the splines line up, this should allow you to remove the small sprocket.

Edit: now I've found my glasses I can see you have removed the small bolts, the only thing that is keeping that front sprocket on would be slight burring from usage, a wee gentle few taps with a hammer might bring the desired effect for you or push it back on and do some minor filing with a small flat edged file.