jetting lrd slip on with airbox lid?

[450raider]

another contributing factor to why my brothers newly aquired R might start like s---, is because it came with a lrd slip on on it and its with the airbox (with k&n inside it) and whoever had it last probably dont know the first thing about jetting (as i myself do not but at least i admit to it), so can anyone whos got this setup or something like it kinda point me in the right direction? like jets, needle, ect. and can i find all this stuff at a honda shop? we dont have the carb off yet so i dont know whats in it and to be honest im a little afraid to find out lol.....

thanks