Ahhhh, the ole YZ brings back memories, especially that twin leading shoe front drum brake. In the dry, worked as well as most disc brakes, in the wet (and I lived in England, so it was ALWAYS wet) . . . . well I reckon the "ohfuckohfuckohfuckingshit" inside the helmet had as much slowing effect as the brake did ! Mine was only a 125 chassis, with a DT200 engine, so I can only imagine how much scarier the 490 was with the same brake setup ! I bought a disc braked 490 years later, and my lasting memoty of that was the Godawful noise the bugger made, as those great big cooling fins resonated. On a freshly rebuilt engine, you'd swear there was a bag of nails rattling around on the top of the piston !