have recently bought a 1993 750w. bike is in great condition but runs lumpy between 3000 and 4000 rpm. Also does not need much choke to start from cold and you can turn of choke straight away. is this normal?. also you dont notice it from cold but as the bike warms up it seems to get more prominant. dont know much about history of the bike but ir was fitted with a cobra can!. not had much time to look at it yet suspect that it may be running rich can any one shed any light on this fault and also how many turns out should mixture screws be
thanks