The TS stuff that comes to mind is: Make sure the fuel line is not blocked/kinked/damaged. Is the fuel filter clogged? If puring some gas in the plug hold gives you some results, that can only mean the problem is with the fuel delivery system. I had a probem like this on my Husky 165BT abd what happened was while I was in heavy brush, a branch cought the fuel return line and yanked it out of the tank.

Thanks i will check that tonight..

Also check muffler spark arrestor screen.

G'day mate!
What was the outcome? My BR400 won't start today either. I did find a loose spade connector. I replaced that then I found a sharp 90 degree bend in the HT lead which stretched under tension. I have made a temporary join in that with a bullet connector. I pulled out the ignition coil and gave the faces on the flywheel and ignition a quick clean. Now I need to know the gap setting for the ignition system between it and the flywheel.
Cheers Kevin.