990 missing/ running on one cylinder after startup

So first the recent history of the bike

Base gasket failed at 7000 miles (including a lot of track play time!)

Replaced it myself and it failed again (ALWAYS ALWAYS ALWAYS make sure you have the right tools before you start a job as you can't estimate torque settings!)

Took engine out again, had a mate/ mechanic replace gaskets again and removed SAS (not 'told' ecu yet so fi light on).

Put engine back in and it would turn but not fire

Dicked about with it for a bit, failed to fix it, sent it to mate again and he got it running.


Now bike finally been ridden again after about 3 years off!

Done 300 miles in last couple of weeks.

Now the problem
Seems OK when ridden (maybe a little slower, could just be my memory, but it does seem harder to wheelie) however if I stop and turn engine off, when I restart the engine feels gutless (maybe running on one cylinder?) and if I whack the throttle open it dies, then lurches, then dies again. Ride through this for a few minutes and seems fine again.

Thoughts guys (and gals) please, what should I be checking

I had a problem similar to this. Mine would idle and miss occasionally and would really miss when ridden over 6k rpms. Turned out to be a loose coil pack on top of the spark plug in the front cylinder. I seated it better to the spark plug and all was fine. Any lights flashing?

FI light is on all the time, which I think isn't what it should be from SAS removal.

Will check coils

if you got a tune ecu cable u can start checing the basics fuel, compression , spark if u have them three working check secondly flys they will give similar results again a cable and tune ecu is your friend ,or it could be something as simple as bike is going in limp mode because of sas removed put sas back on and try cheers bazz