Tiger 955i

Hi, my Tiger 955i has started cutting out, no electrics, no power.
To clarify, I can run it for short journeys up to 90 minutes at which point it will cut out entirely. I can leave if for a few seconds and it will then restart, but then do it again. If I leave it over night it is fine unless I run it for more than 90 minutes again.
I've changed the starter relay and the main fuse, but it still does it.
I've bought a immobiliser loop plug in case its that, but I don't know how to disable the alarm to fit it?
Anything else I could check or any pointers from others if you've had the same issue please?
I've recently changed the plugs, air filter and changed the oil and oil filter.

 

Thanks, I've started checking the wiring and connectors from the batter out, I've done to the alarm and I'll do from the ignition next.

 

No, I do occasionally put it on a charge, but not recently
The last time it happened I was actually camping

 

Ok right, rookie question, where is the crank sensor, I'm working my way through the electrics cleaning and checking connectors for wear and verdigrises'.