OMG, what a bunch of youngins!!!
Here's a pic of me, circa 1966 with my Honda S-90 ( the S was for Sport, not scrambler) that I raced in scarmbles:
Scrambles was the Americna term for what Europeans referred to as MotoCross. There were two basic types of scrambles, the ROugh Srmables and the TT Scrambles, or simply TT ( in European Racing TT refered to Tourist Trophy...road racing on rea roads...the Isle of Man TT). In the US TT scrambles or, just TT, races were held on tracks that were relatively wide and smooth, much like racing on dirt roads. You could also kind of consider them dir road race courses. Not all were real smooth, but they weren't rough, bumpy natural terrain courses either. Most had at least one decent jump in them, much more than one foot. At the speeds that could be reached on many TT course, a jump could result in the bike getting 10ft or more in the air and traveling 50-60 ft befoer landing.
Rough scrambles were held on basically natural terrain courses, the rougher the better. When Motocross first came to the US, they raced the same tracks that rough scrambles events were held on. The difference was basically i the format of the races. Scrambles were more typically races that involved one or two heats and then a final with the finish of the final determing the finish order. Races were typically ran by number of laps, such as an 8-10 lap final. Motocross was run on the same course, but ran longer races, timed, say like 30-45minutes and the race cosisted of two equal length "motos". Winner was determined by the total combiined points a rider accumulated in the two motos. A rider could win overall without actually winning either moto.
Scramblers were the predecessors of what was to later become motocross bikes. However back than it could apply to a true race bike, a bike modified for racing, or a bike built to resemble a racing, or scrambles bikes. Things were much different back then. Many folks raced their street scramblers. SOme even road them to the race. You would get a paper plate with your number on it. You'd take out your headlight lense (and take off the taillight, too) and then tape the number plate over the empty headlight shell. After the race, you put the lights back in and rode home!!!
Well, its late at night and past tis old geezers bedtime, so thats about it for this little abbreviated lesson in motorcycle history from one who lived it!
Oh, BTW...my avatar...that's me on a 1968 BSA 441 Victor Special raced it in scrambles, cross country, enduros.