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Crankshaft repair
Pressing out, aligning, fine balancing, customizing of eccentric crank pins. For racing, the crank pin is laser-welded in order to ensure a rotational stability of the two crankshafts relative to each other.

worb5 vespa lambretta crankshaft

The crankshaft is certainly an important if not the most important component of a two-stroke engine. Especially with Vespa and Lambretta engines there are many possibilities of modification.
There are hundreds of different connecting rod kits with as many different sizes.
There are extensive lists of dimensions and model names. We have many common rod sizes available.
We provide a new rod kit according to the model, but also to measure. If a connecting rod is needed for a conversion, it often has to be reworked.
These revisions are also carried out. Likewise, we stock all the common connecting rod bearings for the lower crankpin, all standard piston pin bearings (10, 12, 13, 14, 15, 16, 18 mm), many thrust pins and thrust washers.

Eccentric crank pins
A small treat for all tuners is the eccentric crank pins. They are specially made and increase the crankshaft stroke by their eccentricity. In principle, it is possible to incorporate such a crankpin into each crankshaft. In most cases, however, a different connecting rod must be used because the lower connecting rod diameter must be larger than in the original state (to get the lower bearing cage on the eccentric pin) because of the eccentricity of the bolt. In addition, in 95% of the cases, the crankcase must be spindled internally so that the connecting rod does not grind inside.
worb5 vespa lambretta crankshaft

These eccentric pins have already proven themselves with the Lambretta on the basis of a 115 mm Rotax piston with 18 mm piston pins (Kawasaki, Suzuki or Yamaha Conversion). The stroke is extended by 3 mm.
In the extreme case, from 64 mm to 67 mm.
But also crankshafts with standard connecting rods can be extended in the hub. For this purpose, the lower connecting rod eye is honed in a specialist company in order to be able to mount a larger bearing. The shaft still has the original rod length and is still for a 16 mm piston pin !!! For example, for TS 1 or RB cylinders with 63 mm stroke (or even 67 mm).

Vespa T5
We also have eccentrics for the Vespa T5. With the T5, the stroke is ramped from 52 mm to 54 or 56.5 mm. For the conversion to 56.5 mm stroke is another Pleul is necessary. It has a length of 110 mm and is thus 5 mm longer than the original. The stroke and the plunger length of the Vespa T5 is compensated by a 5 to 6 mm foot seal. With this stroke, the shafts can also be driven with rotary vane inlet after a machining operation.
worb5 vespa lambretta crankshaft

Customized eccentric crank pins
It is possible to start eccentric crank pins for different crankshafts. For this purpose, the crankshaft must be disassembled, the crankpin dimensions determined and calculated. A production drawing is created. The crank pins are pre-machined from an insert steel, then surface-hardened and finally ground.
Flow-resistant diaphragm crankshaft
The crankshaft is streamlined, fine balanced and polished.
The reworked shaft thus offers a much better flow behavior especially in the area of the inlet where an untreated wave interferes with the gas flow and does not allow enough mixture to pass through. Certainly, a new crankshaft can also be converted. This rebuilding only works with the Vespa in connection with a diaphragm suction connection. The Vespa T5 crankshaft is somewhat more elaborate. Here the "pockets" are also welded on the inside, i.e.. the crankshaft is disassembled, rebuilt and later reassembled. Smallframe crankshafts can also be processed in a streamlined manner.

worb5 vespa lambretta crankshaft

Press the crankshaft
Replacing the connecting rod by another. This is e.g. when using some conversions. Even with extreme engine mountings, it is usually necessary to drive another piston (because of the length and / or the piston pin diameter). If the lower connecting rod bearing or the connecting rod itself is defective, the crankshaft is completely disassembled and a new connecting rod kit (new crank pin, new bearing, new starting disc, new connecting rod) is installed. Certainly, the wave is then aligned and best laser-welded.

Align crankshaft
Sometimes both crankshafts twist to each other. This is done by everyday hard and long driving. However, both crank jacks can also rotate relative to one another by means of a piston clamp. For example, the pic-up inside the rotor, it can be assumed that the crankshaft has a stroke. The shaft now gradually destroys the crankshaft bearings by its "egg". Here, the two crank webs are aligned with each other by means of a special straightening device. If necessary, the shaft can be completely disassembled.
Then the crankpin is pressed again with a highly effective adhesive from Loctite and aligned or better exhausted.

worb5 vespa lambretta crankshaft

Crankshaft statically balanced
If, for some reason, material is removed from a crankshaft (for example, in order to lengthen the intake control time), an imbalance is created that can have a very negative effect. Most of this is already felt in the driving mode at medium speed range.
But also some crankshafts, such as long stroke crankshafts for PX 200 and PX 125, etc., have a strong unbalance at the factory. Actually an absurd - Sadly sad truth. The crankshafts are checked on an extra balancing device and removed from the material so that they are again in equilibrium and run absolutely smoothly during driving. It is also possible for us to equip crankshafts with heavy tungsten weights in order to achieve a pleasant balance factor. This is necessary in some extreme cases.

worb5 vespa lambretta crankshaft

Repair the disc spring
If the groove of the crankshaft ("limanut") stops, which locks the rotor or the ignition point, then this is brought back into perfect condition by skilled welding and post-processing.
A permanent washer spring is welded. This is unfortunately NOT possible for the Kuluseite.
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