Then keyster stuff is crap,
Give rick Oliver a call get some decent ones.

Sfunny. The third post in mentions that they were supplied by RO. Maybe the keyster kits are .....as Hunter puts it "crap", but RO can only supply what is out there and possibly these maybe unfit for purpose or I have a faulty one. I was hoping for something a bit more constructive. The question remains the same. Has anyone had any experience with the keyster kit (needle valve and seat)?

My guess, you had some crap in the tank that got lodged in the tap, keeping it open.
For that much fuel to reach the engine, it means it traveled from the tank and then got passed the carbs, so that needs checking again.
Dismantle the fuel tap and make sure the tank is clean too.

Thanks Speedy. I'm not in a rush to take the tap apart as it appears to function correctly at this moment. My main focus is the carb set up with the keyster needle valves. I was hoping that someone on the forum would have replaced theirs with the Keyster kit and may have run into same issue. I have refitted the carbs, left the tank on and emptied the sump completely and will leave it alone and see if anything makes it way into the sump. If so this will point to a faulty tap and float set up combined....Then I will look at the tap as need be.
Thankfully I have the luxury of another bike at my disposal and can take my time
Cheers for your thoughts.

Been a while but thought I'd post an update. Took out the Keyster needle valves and seats and put the old ones back in , resetting the float heights and voila. She fired up . Has been left and tested over consecutive days and all appears as it should. Will post a comparison pic of the keyster and original needle valve and seat later so you can make up your own conclusion....but hey I ain't bothered.....unless it happens again.....nah.
Certainly had me confused for a while but means I can look at other things now.
Cheers.

Good news