You can put a similar threaded nut on the end of the bolt so the threads are protected and whack the bolt with a hammer.. it's likely that the bolt has corroded to the spacers.. when you get 'em out, put never-seize or some grease on the bolts so it helps prevent that from occuring in the future..
don't use the castle nut that holds the bolt on, they are not very stout and you will damage it, and on Sunday, there's no place open to get another one

If you do use the castle nut, turn it around backwards, and be as gentle as you can. You can also try using a drift or punch to hit the center of the bolt, but still put a nut on it to protect the threads...
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2007 RMK 700 155", 2008 RMK 600 155", 2006 RMK 600 144", 98 Indy 440, 95 Prowler 550 2-up, 1990 Indy 650
RIP, destroyed by fire 1-22-2008

04 RMK 800, 05 RMK 600, 02 RMK 800, 97 RMK 700
http://www.avalanche.org/accidents.php