81 kz400j ignition problems

Hey people,
So I'm having problems with my 1981 kz400j (four), I was trying to start it up after doing it up, and I'm finding that only cylinders 2 & 3 are running, the other two seem not to be. I just installed a gpz550 ignition igniter 1983 (to save money), could this be the issue? I figured because the ic igniter is designed for a four cylinder of similar size that it would still work fine... Am I an idiot? Anyone done anything similar? Thanks.