In 1894, Ernst Sachs began making bicycle parts in his home country of Germany, mainly hubs and bearings. A decade later, the company made the natural leap into motorcycles, focusing mostly on the production of components for other manufacturers. Ernst’s son Willy took over the business in the 1930s and began producing two-stroke engines, and by 1938, the company was selling half a million of them per year.
In the 1960s, Sachs merged with DKW and Hercules, developed the first rotary motorcycle engine, and began selling complete motorcycles in the United States. Introduced in 1968, the Sachs K-125GS Boondocker Enduro was developed for serious enduro racers to compete in the prestigious International Six Days Trial (ISDT) and similar events. A privateer could purchase a Sachs 125 for $600 and it would be ready-to-race right out of the crate.
“With enduro riding, the motorcycle was secondary to the rider in terms of winning, and the key aspects were handling and reliability, which the Sachs offered in spades. The developers were not interested in styling and looks, but efficiency, with every nut, bolt and frame weld designed to help the competent rider come racing out of the mud hole ahead of the pack.” –Clement Salvadori, Rider
The frame had a burly backbone that was 2.75 inches in diameter, with a steel plate to reinforce the engine cradle as well as a bash plate. The swingarm pivot was reinforced via the engine mounting plates — another method of making the bike as indestructible as possible — and the swingarm itself was made of thick-walled 1.65-inch steel tubing.
The perfectly-square 54cm x 54cm, 123cc two-stroke unit-construction engine made 12.5 horsepower at 7300 rpm, eschewing the more sophisticated oil-injection systems of the Japanese rivals in favor of mixing gas and oil in a 25:1 inside the lovely 2.6-gallon tank — fewer components to break. In European tradition, both the shift lever and kickstarter were on the left side of the bike.
The intake system, on the other hand, did show some neat ingenuity. The airbox was located beneath the saddle, designed to keep out water and mud — not unlike we still see today on most enduro bikes — but the Sachs engineers actually cut holes in the tubular backbone of the frame to help route the filter air straight into the 24mm Bing carb!
One of the most interesting aspects of the Boondocker was the triangulated leading-link fork — aka an “Earles-type” fork, as patented by Ernie Earles. The fork shocks boasted dual-rate springs, which reportedly gave excellent feedback to the rider via the Magura bars.
“This was definitely an improvement over the more common, and cheaper, telescopic forks of the era, which had a depressing tendency to bottom out when slamming into ditches and holes, sometimes tossing the rider over the bars.” –Clement Salvadori, Rider
Wheels were 21-inch front and 18-inch rear, and the wet weight of the whole shebang was just 220 pounds! These bikes disappeared from the US market sometime in late 1971.
The specimen you see here is actually a single-owner barn find with only 930 original miles and unbroken chain cases! It has new plugs, grips, rear tire, and gas, and will be hitting the Mecum’s auction block in early 2022. You can learn more and register to bid at Mecum.com.
