Zweirad-Union motorbike 25

„Mofa 25" of the Nürnberger Zweirad Union AG only already fascinates by his appealing appearance. This impression is not least caused by the elegant pastel-white in whom the motorbike is delivered serially. The type 110 (so the Nuremberg two-wheeled vehicle is called „Mofa 25 \ " in the varied type program union) owns a 50ccm-two stroke cylinder-engine with 40 mms of drilling and 39 mms of heave which is already no stranger from the model row of the motorbikes and corresponds in his basic concept exactly 40 km/h motorbikes. Because this engine was brought, however, according to the regulation of the legislator for the motorbike on a maximum speed of 25 km/h, now he owns so high security reserves as they are probably only to be found rare, otherwise, in the vehicle construction. Pure according to calculation, from the side of the journey opposition looks, one needs since to the achievement of a speed of 25 km/h about 0.4 HP .i One does not get by with these 0.4 HP, however, of course in practice completely because one wants to go by the motorbike also in the mountains. Therefore, one needs about one achievement which lies something about the double of these 0.4 HP. However, one renounces a precise achievement information with this vehicle type because 25 km/h are prescribed by the legislator and one fears to unfold a „PS war \ " by achievement data only once more as he came already repeatedly in the development of the small engines of the outbreak.
As with the „big brother \ ", the motorbike engine TO, needle bearings with cage are also used with the engine „Mofa 25 \ " for connecting rod and gudgeon pin storage. The crankshaft is stored in ball bearings. A fact which allows to become widely safe overwinding the engine on strong  descent route Indeed, one will come as a customer quite seldom to such overspeed scopes because one can be quicker since much even if one goes in the slope without engine, i.e. with inlaid running dry!
The cooling of the engine takes place via the wind, thus not with a blower. But this cooling, which we could determine on our trip by the mountains of Frankish Switzerland clearly, are sufficient for this Mofa engine of the two-wheeler union perfectly. A noticeable power loss was not to be determined also during repeated uphill drive with upward gradients of 18 and 25%. Even starting on an upward gradient of 18% was with operator's weight of 62 kg still without help of the pedals after such repeated uphill drive under high-summer temperatures possible. A really amazing achievement for this 25-km/h-wheeler!

So that now however findige of Bur this driving licenceless Mofas do not bring the engine on the achievement of the moped, different safety precautions were met, which make an increase in output of the small engine practically impossible. Thus one is with the cylinder welded, hardened steel socket in the suction port, which excludes an additional extension of the suction port cross section with normal means. In addition it comes that the cylinder mounting takes place differently than with the moped engine, so that a replacement of the complete cylinder is likewise not possible against a faster engine. In addition, by a change of translation this vehicle cannot be made faster, because the rear chain wheel with the hub was riveted and additionally the mounting of the front chain pinion was solved in such a way that this cannot likewise be exchanged from space reasons against a larger.

The Bing carburetor possesses a passage of 9 mm and ensures by its Startappliance an easy starting of the engine at all outside temperatures. By the hollow guidance head restraint vine of the vehicle frame the intake air arrives at the carburetor, whereby this prop exercises the function of the sucking in silencer at the same time.

A three-disk multiple disk clutch in by diagonally-interlocked spur wheels formed the primary transmission, in the oil bath constantly, provides for soft scolded and starting. We could determine that particularly with starting attempts on a 18% upward gradient. It was shown that even with some higher performance engines, which were not equipped with a in such a way soft-seizing clutch starting was no longer possible there. With the engine (likewise as with the large brother) to a block combined the transmission is designed and with drawing wedge is switched as two-speed transmissions. Thereby the operation smoothness of the circuit, which takes place via a scolded turning handle at the steering wheel over a push pull cable via shifting the drawing wedge completely stored in the drive shaft particularly, surprised. Although also the arrangement could appear perhaps somewhat unmanageable to a turning handle circuit at the steering wheel for woman hands, then it is nevertheless straight with this Mofa by the omission of the third course, which is not really needed, easily to operate. The engine lets itself just as easy set also with its PedalTretvorrichtung, which is accommodated in the engine transmission block, on. Coldly it willingly already starts as also warmly after a quarterly revolution of the pedals. The Tretkurbeln can be revved up with pulled clutch as well as running engine easily. To know is particularly important while driving downhill, on which the engine in the no-load operation runs. One can, as already said, with this engine one please-strains with inserted no-load operation as with a bicycle to put back, one must however makes certain that thereby the engine likewise runs. One may not turn thus the engine off by any means completely, since otherwise pedals while driving any longer cannot be moved and so possibly an unfavorable position for the manipulation of the resignation brake arises. The electric current for ignition and lighting is supplied by the flywheel light magneto ignition sitting on the left crankshaft side. The achievement of this plant amounts to 17 Watts with a tension of 6 V. The round headlight of the Mofas possesses a 15-Wattpear for continuousdipped the headlights light, which is completely sufficient for the trip achievement of the 25-km/h-Mofas. A speedometer is in series inserted.