Werner Koch’s conversion of a Suzuki GS 400 E


Werner Koch's conversion of a Suzuki GS 400 E
Werner Koch

Service: Suzuki Scracer 402

Werner Koch’s conversion of a Suzuki GS 400 E

Content of

The dreary winter is over. Now it is high time that the Suzuki GS 400 E in a new look, a mixture of scrambler and dirt track racer, learns to walk.

B.It couldn’t have gone better. Just on the first sunny day after a lousy long winter, the Suzuki GS 400 E – or better: what is left of it – rolls off the lifting platform. Flood the carburetor, flick the ignition switch, the starter cranks, and a blink of an eye later the twin is mocking healthy and lively. Scrap gets quick – who would have thought?

Around 120 hours of tinkering and handicrafts were necessary to put the Suzuki in a completely new look. But not only the shell, the function must also be right. After all, the Scracer 402 project is not designed for the showcase, but for everyday use. At the same time, the MOTORRAD CLASSIC editorial team would like to answer a question that has been on the scene for a long time: Can a 30-year-old chassis with more stable but contemporary components and technical improvements be brought up to the level of modern, comparable machines in detail??

The basis for this was to remain largely the same as the GS 400 was delivered at the end of the 1970s. MOTORRAD CLASSIC only gave the main frame an additional tubular strut on the steering head, which is 3 degrees steeper than on the standard machine, now 66 degrees. This reduced the caster from the original 94 mm to the borderline 71. In order to limit problems in driving stability, the use of the aluminum swing arm of the Suzuki GSX-R 750 increased the wheelbase from 1385 to 1405 millimeters. The size of the 33 mm telescopic fork, like the simply clamped bridges, should not be changed.

Werner Koch

The Scracer 402 also cuts a fine figure without a cover.

The completely new design has changed the weight distribution of the Suzuki. Of the total of 163 kilograms (ready to drive and with a full tank), a good 52 percent weighs on the front wheel. In order to counteract the higher wheel load, the bores for the compression damping were first welded, then almost halved with a 3.5 mm bore in the free area, while the standard fork springs were initially retained. The hydraulic end stop, however, has been massively shortened to prevent the annoying suction during braking. The piston presses its way through the stop pot filled with fork oil to the bottom.

Because the old fork systems do not have a shuttle valve that releases the piston again without resistance, the piston has to move out of its position when it rebounds against the negative pressure. Sometimes the fork can no longer rebound quickly enough after a sharp braking, the front wheel begins to jump, and the grip breaks. So that the fork does not immerse as far as it will go even without the hydrostop, the fill quantity of the 20 mm fork oil has been increased so that the tight air cushion of 110 mm creates a stronger progression.

With wider Conti Twist Supermoto tires in a soft rubber compound, in the front in the format 100 / 80-17, rear 130 / 70-17, the Suzuki should also be suitable for tight cornering and rapid lean changes. In terms of key data, the mutant takes on any modern sports suspension.

The Scracer 402 only carries the bare essentials. Tachometer, gear indicator, headlight, passenger pegs, air filter box – all ballast. For the intended TÜV test, two 40 mm headlights are hidden under the fork bridge, at the rear a small multifunctional rear light grafted onto the tubular support, framed by two small indicators.

The wide, black anodized aluminum handlebar underlines the dirt track appearance. Coarse-toothed enduro pegs replace the wrought-iron footrest supports. On the left, a smooth lever mechanism pushes the gear wheels into position; a ribbed contemporary pedal on the right activates the hydraulically operated rear brake. The chain and the sprocket come from Enuma, which in the aluminum version harmonizes perfectly with the color: Except for the tank, only silver, aluminum, chrome and black can be found on the Scracer. Turn signals and switch units are of course excluded.

Werner Koch

A centrally placed speedometer is enough.

Because no suitable seating could be found, the seat bench was formed from two millimeter thick aluminum sheet and welded. A recessed shaft bunkers the battery, the cushion itself arches over a GRP base plate that is screwed to the aluminum substructure. In order not to break the budget of 3000 euros, the series tank was retained. However, the sheet steel part had to undergo a tight deformation on the floor so that it fits the line sloping slightly forward. Slightly drawn in on the side, the tank is given a pair of classic knee cushions – and of course a chic paint job.

The Scracer 402 will be featured in the next issue of MOTORRAD CLASSIC in the typical Suzuki blue. Then it will also show whether it meets the expectations of a real scrambler – or not.

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