Maiden voyage of the Scracer 402

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Maiden voyage of the Scracer 402
Rossen Gargolov

Service: Suzuki Scracer 402

Maiden voyage of the self-built based on a GS 400 E.

Content of

The way from the hand-drawn sketch to the rolling chassis has been made. Now the MOTORRAD-Classic self-construction shows on its maiden voyage whether the plan is working.

E.Regardless of how accurately the welding seams were drawn and the frame reinforcements calculated: If the self-made construction ironed over bumps at full throttle during the first test drive, the brake caliper snapped at the windshield at full speed, making it squeak and smoke, there is no uncomfortable feeling from: Withstands the in-house construction in practice? Or does what should not break under load? Just on the new central spring system, enormous forces and moments balance and press. Due to the ratio between the rear axle, the strut mount and the swing arm axle, the aluminum swing arm and the frame tubes act on the aluminum swing arm and the frame tubes at maximum compression travel of 750 kilograms. If the dynamic factor of the damper force is added, the value is around one ton. It is therefore advisable to install a full safety cushion and to forego daring lightweight construction.

With great respect, the pilot with the Scracer 402 rolls leisurely over the undulating slope on the MOTORRAD test site in Neuhausen ob Eck. To be on the safe side, the test driver is in a modern racing suit, protected all around with protectors and high-tech material, just in case. Then the first check, the unique specimen is meticulously checked and appraised: welded seams, frame tubes, swing arm bearings – everything is stable and solid.

A rare case: maiden voyage without tinkering and screwing

Even the twin, made up of two more or less defective engines, purrs surprisingly quietly and reliably. The occasional delicate blue smoke from the megaphone silencers indicates a slight loss of oil, but this is not yet really measurable and is not accepted. But he lets the idea flourish to bring the unique specimen up to speed with a 50 hp engine.

The pace becomes sharper, the queasy feeling gives way to joyful curiosity. For the first time it’s full steam of all 27 HP over the long straight, into the bump, without twitching over joints and transverse grooves. Although the fork and shock absorber were completely rebuilt and only adjusted based on the bare figures of weight, wheel load distribution and gear ratio, the damping and spring rate fit very well. The Wilbers shock absorber in particular responds extremely sensitively, builds up ample damping on heavily undulating road surfaces and keeps the rear stable at all times.

Next exercise: full in the irons. Due to the front-wheel-heavy weight distribution, the tire clings to the asphalt. Gently but firmly, the rear wheel lifts off the ground or dances spectacularly across the track.

According to data recording, the mutant of scrambler and dirt tracker decelerates at least as good as any new motorcycle at 9.8 m / s². It is all the more astonishing that the delicate 33 mm fork under the brake system mounted on one side only twists minimally and does not break through. A massive, four millimeter thick aluminum bracket, welded to hand-hammered fender half-shells, effectively counteracts the feared torsion. Only when the braking section has been completely erased with black stripes does the front 320 disc also take on a slightly bluish color, but no trace of fading. Brake test passed, please go to the next test.

Curves, the salt in the soup

The dear reader may apologize for the fact that the eternal comparison with the bicycle is used to describe the agility, but in the case of the Scracer 402 we come pretty close to the often abused, excessive exaggeration. Even if it weighs a good 160 kilograms, the Suzuki throws itself at the thought of the next bend – snap! – in an inclined position. Which of course is also due to the fact that the wide tubular handlebar converts every gentle impulse into jagged cornering.

But, to be completely honest, the designer overshot here. Handiness or not: If the bike tips over in an inclined position without a serious command and this can only be stopped with a determined steering impulse towards the inside of the curve, the horse is simply sick.

Another symptom of the same malaise is the inclination in the circular path that has to be constantly corrected. At more than 40 degrees, any feedback goes flat and the front wheel seems to fold in for good. Quickly set alternating curves are as light as a feather, but also suffer from the over-nervous wobbly.

What went wrong? The steering geometry with the extremely short caster of around 70 millimeters and a steering head angle of 66 degrees could theoretically be the cause. But the gut feeling contradicts it, also because the Scracer drives very stable straight ahead. And: The Scracer feels right at home when turning and in a moderate incline of up to around 35 degrees, only then does it get critical.

A look at the tires brings a hot lead. The Conti Supermoto rubbers are unusually pointed; their contour resembles the legendary Dunlop KR racing tires of the 60s and 70s. The smooth transition from straight-ahead driving to an inclined position, which can only be felt on tires with a uniform curvature, is missing. The current soling can either be straight ahead or on a full slope; in between there is only unsteady tilting.

The realization calls for action: Instead of new triple clamps with less offset for greater caster, new Conti tires are ordered and the TÜV date is nailed with great optimism. After all, the Scracer 402 is not made for the display case, but for the exit. Was it really the tires? Or is the whole chassis geometry useless? The explanation of the adventurous self-construction follows in MOTORRAD CLASSIC 6/2010. Until then, we may still be working on the design. Many a detail and so many lines still leave room for improvement. Some MOTORRAD CLASSIC readers saw it that way too and spoke up via email. What do readers think of the idea of ​​mixing the new with the classic? You can read this on the next page.

Material costs and working time

A lot of small items such as brake calipers, fittings, cables and brake lines came from the private workshop fund. If you put a third of the new price for the used parts, the Suzuki conversion comes to around 2200 euros in material value.

300 euros remained with the accessories specialist Polo for the lighting system, handlebars, electrical accessories, sealing kits and Simmerrings. The megaphone exhaust system was bought from Detlev Louis for just under 100 euros – (still) without the approval of the TÜV, but with very good soundproofing. The impact-resistant Gotz powder coating of the frame, main stand and small parts caused costs of 360 euros, the painting of the tank and seat was compensated with 180 euros. The specially made Wilbers shock absorber cost around 450 euros.

Until the motorcycle has received the approval of the TÜV and all small and large defects have been fixed, the Suzuki GS 400 E, which was purchased for 650 euros, has totaled around 150 working hours.

Reader opinion

I’m glad that the guys can’t see the “original” ones anymore. In fact it is the case that motorcycles (I think) more than a car are very often individually adapted to your own taste through small modifications. Conversions that are really successful are very popular. But you also sit more relaxed without a stump with superbike handlebars, which is simply great for an old man’s device. Individual solutions to problems (how do I build what and where) are asked for correctly and are imitated / bought immediately.
Holger Mertens, by email

Dear Mr. Koch, I would like to thank you for the good idea and the article! At the same time I would like to encourage you to do more such interesting conversions. I prefer this type of remodeling, and I do it this way myself. Therefore, I would like a more detailed presentation of the project with a lot more detailed pictures in your booklet after completion! And above all: when and where you can admire the good piece live?
Rudiger Muller, Ravenstein-Oberwittstadt

After completion, the Scracer will be shown at some classical events, where and when is not quite out yet. We will inform about this in the magazine.

Hello Werner! Well, I think it’s great how carefree you combine old and new. So I’m excited to see what the finished motorcycle will look like and, above all, how it will drive with it.
Peter Hahn, by email

“Scracer” is not only possible, it must! Very nice project – the combination of imagination and budget. The variety makes the motorcycles interesting; new and old, top condition and wreck, original and crazy rebuilt – everything has to be. I also want to know how exactly model XY looked absolutely original, but I don’t have a single original device myself. So let’s enjoy the letters to the editor, thank God 80 million Germans don’t have the same taste.
Christian Rolfs, Fredenbeck

Turning a rather unspectacular motorcycle into such an eye-catcher has something to offer. However, I also have criticism: the exhaust system is too high at the rear. That looks exaggerated and disturbs the tank-bench line. If the silencers ended just below the bench, the whole thing would look much more harmonious. I also don’t like the front unreservedly. I think the idea with the headlights under the steering head is brilliant, but the start number board looks unfinished. With the year of construction, ox eyes should be enough as indicators. The start number board would not need to be folded to the side, but could also be used e.g. B. have a round shape. The clunky speedometer that protrudes over the number plate doesn’t work at all. I’d rather not say anything about the phallic rear light. Gripe at a high level, the tank-seat line and especially the swing arm conversion and the modifications to the frame make a difference. Hence the budget of 3,000 euros. That’s a lot of wood. I don’t know if I would put that in a 400 cc motorcycle.
Jorg Schneider, by email

I am following the history of the conversion of the GS 400 with interest. Personally, I think the combination of technology from different motorcycle generations is okay. A note from me about the Scracer. I would like it better if its model had the exhaust system as an underseat version or in the style of an English scrambler. I also own a GS 400 and am thinking of putting a personal motorcycle on the wheels. Since I also have other components from different motorcycles in my pool, I will soon start combining them. Let’s see what happens. Otherwise keep it up. I look forward to new information about the Scracers.
Bernd Ledig, by email

If your conversion is on the wheels, please report!

I think the glass bead blasted engine parts and the gray frame are very successful, and the lines of the tank with the frame are very consistent. I find this area in front of the seat above the shock absorber mounting (and under the tank) to be a bit annoying, because something is missing in the side view. If the upper line of the silencers were to be oriented towards the frame tube, then I think the rear wheel would not look all the way back. But what really bothers me is the worm attachment at the back – it doesn’t fit at all. So either I would turn the rear light by 180 ° and integrate it into the bevel of the rump or try it right away with these combined Kellermann brake / flashing LEDs. And then attach a nice aluminum bracket (see e.g. Totti 250) for the tiresome number plate.
Roman Moser, Weilheim / Obb.

If it passes the TÜV in one way or without major changes, it is a dream! Most mopeds that are built with great financial outlay and / or without street approval and / or without a look at drivability are uninteresting – anyone can do that. The Scracer is really great; I am very excited! The moped was one reason to buy the MOTORRAD CLASSIC.
Stefan Sauer, Monchengladbach

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