I fitted an RM370 VM36 to my TS400 and while a bit doughy it ran pretty well. Oldfart then fitted a 'new' PE250T VM36, increased only the main slightly and it went like a cut snake in comparison. Can find out the main size but 310 rings a bell. The only thing is the RM370 and the RM400C 36mm carbs don't come fitted with an idle screw. I like the idea but on a trailie it'd be a right pain. PE250 carb could be the go but another wee problem maybe the inlet size for the rubber airbox boot.