parts for a streetfighter!

i bought a 1986 gsxr750 to replace my poor lost TL (i know some of you may think thats a step backwards but its 190kg with 100bhp at the back wheel, i'm not complaining), and its been going great till just a couple days ago. well pretty much yesterday though sunday was a little glitchy. feels like its running on 3 cylinders, maybe even two sometimes, pulled out sparkplugs yesterday, they're brand new. mechanic mate said, might be distributor leads but i'm hoping its not cos it turns out they're ...