Quick, what has six speeds, and twelve neutrals? If you’ve been around dirt bikes for any amount of time, you’ll know that answer: Anything with a DKW motor in it. 
The 125 that started it all, the 1949 RT125 (Harley Hummer, BSA Bantam, Yamaha RY125, etc.)
The Sachs/DKW/Hercules transmission was a 1930’s design that used a “T-Bar” shift selector, with detent balls in a hollow shaft, and a saw-toothed selector, to move the shift forks instead of the slotted shift cam we all know and love. While this design might have worked great on mopeds, or 50cc kids bikes, the transmission didn’t hack it for the rigors of competition motocross.
The 125 Motocross put out respectable power for a 125cc two stroke of the time, and had to be “kept up on the pipe” because of the porting (especially the GP motor). This manifested horrible performance from the ancient gearbox, and unless it was kept in perfect adjustment, the rider missed more shifts then a Japanese factory worker hooked on ice & sake.
Let’s take a look at this fabled marque, but first some basic history of the DKW/Sachs/Hercules is in order.
At one time DKW was one of Germany’s leading automobile/motorcycle producers (also branded as Auto-Union). It all began with a toy two-stroke motor, hand-made by a Danish steamfitter named Jorgen Skafte in 1919. It was called “Des Knaben Wunsch” or “The Boys Desire” in Engrish. I can imagine a toy cannon, or steam engine, but a two stroke motor? Man, those Kraut kids were on it…”ACHT FRANZ I ASK YOU NOT TO PLAY WIT DAT SMOKEY TOY MACHINEZIE IN DER ROOM! RAUST!”
1969 Sachs 125 MX
And from those humble beginings ( I love that phrase) sprouted a company that designed and produced some of the wildest two stroke designs in history. From supercharged motorcycles that smashed land speed records, to racing autos that dominated rally car racing, DKW was on the leading edge of all things two stroke in the performance game. 
1970 DKW 125 MX
DKW also pioneered a fairing called the “dustbin” that was outlawed in 1958 after England denouced it for being an un-fair advantage against its big thumpers of the day (they claimed steering lock, and wind stability but we know better).
Near to the end as a major player in the auto/moto world, DKW/Sachs produced a nifty 125cc Motorcoss machine that was a top competitor of it’s day. Utilizing a leading-link front suspension, light-weight design, and a powerful motor, the DKW was at the top of the 125 MX food chain. If you went to any small-bore MX race in the late nineteen sixtys to middle seventies, you could count on a bunch of DKW/Sachs machines being on the start line. You could also count on hearing many missed shifts throughout the race, as GP engined “B” series Sachs and DKW riders searched in vain for that elusive next gear.
Nothing like hitting a berm at speed, and trying to go down one gear, only to find yourself in neutral. Whoeeee, over the berm you went. Or stomping frantically on the shift lever, and going nowhere, while the motor screemed zillions of RPM and everything but the water truck passed you. Such was the Sachs (or DKW). And if you had a Penton, Tyran, Ancillotti, or other DKW engined bike, that went for you too.
Expensive, hard to install and adjust kits were sold to aid the lousey shifting (KOBA), but nothing worked except the use of the clutch and a deliberate shift. I remember being in World Cycles as a kid, watching the German mechanic Max instal and adjust KOBA shift kits on DKW motors, with two dial indicators, prussian blue dye, and lots of cursing. Every few minutes you’d hear Max curse in German, followed by the ping of a 10mm wrench as it riccochetted off the shop wall. Madness. 
Alas, by the late nineteen seventies all was not well for the Sachs (Sachs asorbed DKW & Auto Union in 1965, but kept producing DKW motorcycles), and even the upgrade to conventional Betor forks couldn’t save the Sachs from stopping USA imports around 1978, when the 250 came out. Sachs still sells mopeds, bearings and shock asorbers in Europe, but the days of being a major force in motorcycle development and design are over.
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