SIP Vespa GS3 150 "Streetracer - Custom scooter
SIP co-founder and managing director Alex about his Vespa GS 3: "The GS3 is without a doubt one of the most beautiful Vespa models. At the beginning of 2000, I bought one of the last German GS/3s to come off the production line in Augsburg. The scooter was a garage find. It was disassembled into all its individual parts and nicely packed in boxes. Markus Wessner, who was still working at SIP at the time, then set about restoring the old lady over many years. The goal at the time was a perfect restoration of this German cult model, but the patina of the scooter was to be preserved."
"Markus is now a mechanic at Jockey's Boxenstop, but not only did we stay in friendship, but we also kept the goal of the GS restoration in mind. All parts that were originally galvanised were not replaced by new parts, but refurbished and then galvanised again. The rear shock absorber was overhauled and the aluminium parts were ground and polished. The frame was slightly warped and had to be straightened. The gearshift and throttle pipes were completely oxidised together with the handlebars, etc.! So the usual restoration madness. The scooter was painted several times with nitro varnish, because unfortunately the rubber parts reacted with the varnish and so some areas had to be refinished. The silky sheen of the original nitro paint is now as subtle as it was back then."
An update for the Vespa engine
"The engine was given a general overhaul. As this project took many years, various parts were added. With the appearance of the QUATTRINI M1XL 172 cc direct intake, it was immediately clear that the GranSport should not only be called that, but also live up to its name in terms of performance. The focus was on an original look and therefore the conversion to a PX engine was out of the question. The housing was welded on, spindled and the cylinder stud bolts were moved. With a suitable connecting rod from Jockey's Boxenstop, in connection with a specially made crank pin, the GS crankshaft was made suitable for a Quattrinita. With the help of an 8 mm thick foot gasket, it was possible to defuse the cylinder a little in terms of the timing. Since the original GS gear ratio is too short, we had a primary gear ratio made by DRT. It fits very well with the engine power and was therefore included in the programme. The clutch also has to cope with the power, so an original Surflex base plate was upgraded with a specially made MMW clutch basket, the 4-disc Malossi linings and standard clutch springs. This clutch copes very well with the power and is also very comfortable to pull."
Last steps
"The 172 is now breathed by a DELL`ORTO VHST 28 carburettor in matching vintage red. For this, the frame had to be trimmed minimally. The intake manifold did not fare so well. It was completely reworked and the connecting piece between carburettor and diaphragm was manufactured by Jockey's. For the ignition we begged Tino Sacchi to make the Vespatronic suitable for the oldies. So the GS could be equipped with a Vespatronic. Gone is the trouble-prone contact breaker ignition. The exhaust is a PEP 3.0 in the Sport Replica look, adapted to the GS housing. The sound is very pleasant and harmonises wonderfully with the rest of the engine."
"The scooter was then perfectly set up by Jockey's Boxenstop and cleared at the MOT. The 19 hp of power is delivered to the road with powerful thrust. With this setup, the GS/3 can now keep up with any touring 210 and is stable too."
"My big thanks go to Jockey's Boxenstop for the engine tuning, TÜV and the registration service, Stoffi for the paintwork and Markus Wessner for the restoration."
Parts list
Frame
chassis
Engine
QUATTRINI M1XL 172 modified
Primary gear ratio MALOSSI 24/63 modified to GS/3 and DRT Clutch gear wheel
Clutch basket MMW GS/3
Ignition Vespatronic GS/3
