Hey mate when they are on there for a while they will stick... best way is to lever it off very easy, try not to lever on anything that will bend etc all common sense.
The other thing is, where the nuts are on, there are little rubber seals with metal caps... you will have to pull these out as the sorta make it harder to lift the covers off. I find the best thing to use is a pair of needle nose pliers.
Basically before i read your last sentance was just gona say take it off and try, and worst case just put the old bigport covers on.
Word of advice too, if you got the time and money get new seals for the nuts (about $20 i think) and some gasket glue to go between the cover and the head. its not nessecary but just saves doing it later and further prevents oil leaks..
Hope that helps bud
