My 2016 Sherco was running sweet ( after ditching the Dunlop tyre ) rode my first trial on it Sunday and it was fine for 95% of the trial. Last two sections it started to die on my it quickly fired straight back up, I didn't think anything of it at the time probably just a bit of debris in the card. It fired up I rode the last section and the stuck it back in the van.

I cleaned out the carb blew all the hoses through with a high pressure air gun. I also empties the tank out and changed the spark plug as a token gesture. I took it out practicing today and the stalling got progressively worse, it currently runs for a minute or two then just cuts out intermittently.

Has anyone seen or heard of anything like this before ?

we had the same,it was a dodgy fuel tap - put it on reserve !

Take it back to where you bought it.It must still be under warranty.You ve done the obvious things and it's still not right

Thanks for the responses, turns out it was a dodgy kill switch.

I guess we know what Beta did with the leftover stock of kill switches.