ok so i picked up a 05 DRZsm that has a full yosh exhaust and K&N air filter. Im pretty sure it hasnt been jetted (previous owner didnt know for sure because he didnt put the exhaust on). It pops on decell REALLY bad. also unless you are hard on the throttle in any gear its kicks and sputters. Am i correct in thinking it has not been jetted? Also is the DRZ very hard to jet? I am located just south west of indianapolis, IN so that give you an idea of elevation (i think about 800ft above sea)

any insight would be great guys and thanks in advance.