Retrospective: Sachs K-125GS Boondocker Enduro: 1968-1971

(This Retrospective article was published in the February 2008 issue of Rider.)

STORY by CLEMENT SALVADORI • photography BY Gary Rosa

The Europeans took off-road competitions very seriously in the 1960s, especially events like the International Six Day Trials.


The nice thing about the ISDT and similar events was that a privateer could compete, as expenses were, by racing standards, minimal. And when the Sachs 125 came along in 1968, here was a ready-made, competitive machine available for $600.

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.

There was nothing extraordinary about the two-stroke motor—a perfectly square, 54mm x 54mm, 123cc piston-port single that—using a 9:1 compression ratio—was rated at 12.5 horses at 7,300 rpm. The cylinder head had lovely longitudinal finning. The Sachs did not have one of those fancy oil-injection systems that were mandatory on the Japanese two-strokes, preferring to stick with the old-fashioned method of mixing gas and oil together at a 25:1 ratio in a 2.6-gallon tank, feeding into the combustion chamber through a 24mm Bing carburetor. ’Tis a gift to be simple, less to go wrong, etc.

1970 K-125GS Boondocker Enduro.
1970 K-125GS Boondocker Enduro.

The air filtration system showed sophisticated minds at work. Under the saddle was a big airbox, the top secured by a large wing nut, and inside a modern Fram filter wi­th a paper element. The box’s design was intended to keep water and mud out. In order to get the filtered air to the carburetor in the most direct manner possible, the engineers actually cut holes in the large tubular backbone frame and routed the oxygen straight through. Very neat, very Sachs-ish.

A very brief history of Sachs is in order. Ernst Sachs began making bicycle parts in 1894 in Germany, and developed a very successful business providing hubs, bearings and other bits and pieces to various companies that made bicycles. In 1904 the company got involved in building motor­cycles, but soon realized the real money was in manufacturing items that other motorcycle builders needed. In the 1930s son Willy took over and began producing small two-stroke motorcycle engines, which he sold to a variety of companies; in 1938 Sachs sold more than half a million of its motors.

1970 K-125GS Boondocker Enduro.
1970 K-125GS Boondocker Enduro.

World War II came and went, and in the 1950s the demand for motors was high. In the 1960s several motorcycle manufacturers merged with Sachs, notably Hercules and DKW. As an aside it should be noted that Sachs developed the first rotary motorcycle engine, which appeared in the 27-horsepower Hercules W-2000 in 1974. Sachs began selling complete motorcycles in the United States in 1968, with the
125 Scrambler (no lights) and Enduro (lights) models being the largest. “Sachs” was written on the engine cases, gas tank and brake hubs, but the little identification plaque on the steering head read “Hercules.”

This unit-construction 125 engine ran the power through a gear-driven primary and five-speed transmission, with shift lever and kickstarter on the left side; very European. On the early models electricity was provided by a Bosch magneto, with an energy-transfer system that could be used to power the lights. In 1970 a six-volt battery was fitted in order to keep the U.S. Department of Transportation happy, as the DOT wanted lights whether or not the engine was running.

1970 K-125GS Boondocker Enduro.
1970 K-125GS Boondocker Enduro.

All this sat in a most commendable frame, with a big backbone 2.75 inches in diameter, making a long curve from the steering head down to the rear of the engine; twin downtubes curved under and cradled the engine. Reinforcing the cradle was a flat piece of steel at the front of the engine, which also served to protect the cases from rock damage, and extended to a bash plate.

The swingarm pivot was reinforced by the engine mounting plates and was very rigid. By today’s standards the swingarm itself looked rather lightweight, using steel tubing of 1.65-inch diameter —but the wall thickness ensured sufficient strength. The ends of the swingarm tubes had been carefully flattened to give more purchase to the axle.

1970 K-125GS Boondocker Enduro.
1970 K-125GS Boondocker Enduro.

A pair of non-adjustable shock absorbers with single-rate springs gave more than adequate travel at the back. Sachs’ presumption was that the Boondocker would be set up for the individual rider, so rather than having the weakness inherent in adjustability, the rider could fit new springs if he or she so desired.

At the front was a triangulated leading- link fork, commonly referred to as an Earles-type fork. Ernie Earles had a good patent on his design, so he probably got some royalties from Sachs. The shocks on the fork had dual-rate springs, and the system provided excellent feedback to the handlebars. 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.

1970 K-125GS Boondocker Enduro.
1970 K-125GS Boondocker Enduro.

The Magura bars were a nice expensive touch, and the ball-end brake and clutch levers were made of malleable aluminum which would bend rather than break should the ground come up awfully fast. The foot levers were of the same material, allowing them to be bent back to the proper position after a fall. A hand-tightened steering damper was right above the steering head, useful at speed. The headlight had that traditional German push-down ignition “key,” making the simplest of electrical connections. The speedo went to a rather optimistic 80 mph.
The wheels were an 18-inch in the back, with a 3.50 tire, 21 in the front, with a 3.00. Single-leading-shoe drum brakes were fore and aft. The wheelbase was a tight 52 inches, and the wet weight of the early Enduro models a miraculous 220 pounds, about 25 pounds more than the Scrambler version. When the battery was added in 1970, that meant a little more weight.

Sometime late in 1971 Sachs decided that its motorcycles should be sold under the DKW badge, and the Sachs enduros and scramblers disappeared from the U.S. market.



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