T'Cat YZF 600R

Hi,

Hope someone can help as i'm running out of ideas!

I have a '99 thundercat which starts up fine on all four cylinders.

After around 5 minutes or after the bikes warms up I lose cylinder 1 and it mis-fires.

I have checked and replaced the following

ignition coil 1 & 4 replaced

Plugs gapped and changed

New Air filter

Carb stripped and needle cleaned (head 1).

Could it possibly be ECU/CDI

Any ideas would be much appreciated.

Thanks,

Dave