Originally Posted by mtothef
first there were reed valves.
before that, there were plain ol' piston port inductions or rotary valve intakes. god, i'd almost forgotten the days of accidentally loading up a bike and having to sit there with the throttle wide open while the bike popped and sputtered and cleared itself. yamaha were the ones who widely popularized reed valves, although the CR honda was the first legitimate jap MX bike and the repercussions of its introduction led to the rest of the japanese going crazy.
The first thing we would do on a new bike was pull the cylinder and grind a little bit off of the intake skirt and mod the intake holes on the piston. That and maybe adjust
the expansion chamber..............as if we knew what we were doing!