Xj600 85 no spark

[Cb500w98]

Trying to get a spark on the above bike checking by grounding the plug to the engine case but getting nothing I got a brief spark on one the cylinders but now am getting nothing. The bike does turn over and I have power at the coils, ignition fuse and power to the tci the coils are after market ones. We're do I go next pick up coils next? trying to trouble shoot various components in the ignition system before I start buying anything.