Hi, i just bought a 1990 454 LTD and i was wondering if anyone knew common problems with them, that i can fix before i start riding???

Edit: There is a problem with the carbs leaking gas....

So me and my friend are getting them off today, see what we can do, if nothing, take it down to the local bike mechanic. If, in the crappy case, that i have to buy new carbs, is there any place i can get them used?? my friend seems to think that the ninja 500 carbs will work, any thoughts?