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The crankshaft is an important maybe even the most important component of a 2-Stroke engine. Especially on the Vespa and Lambretta engines there are a lot of possibilities for modifications of the crankshaft.

There are hundreds of different connecting rod kits with just as many different dimensions. We have extensive listings with dimensions and model identifications. We stock many connecting rods in common dimensions. (see Onlineshop)

We order connecting rod kits either after model identification or after your measurements if we can find something comparable. If you need a connecting rod for a conversion it may often need some modification, we can do this for you. Also we stock all common big end bearings, and small end bearings (14, 15, 16, 18 mm), many big end pins and thrust washers.(see Onlineshop)



Connecting Rod Kits Wiseco, ProX, ...

We can deliver various kits from Wiseco (Hot Rod) and ProX. We have some connecting rods in stock.(see Onlineshop)

Excentric big end pins
Goodies for all tuners are the excentric big end pins (see Onlineshop). They are custom manufactured and increase the stroke because of their excentricity. Generally it is possible to put such a pin into every crankshaft. In most cases a different connecting rod has to be used, since the pins diameter has to be increased due to the excentricity. (to be able to fit the big end bearing over the pin, etc.).

Lambretta
Excentric big end pins have shown to be a good fit for the Lambretta paired with a 115mm Rotax connecting rod, with 18 mm piston pin. (see Onlineshop) (Kawasaki, Suzuki or Yamaha Conversion). The stroke is increase by 3mm, in the most extreme case from 62mm to 65mm. But also standard crankshafts with standard connecting rod can be modified to increase the stroke. To achieve this, the standard connecting rods big end is honed in a German professional company to accommodate a larger bearing. This enables to work with the original connecting rod length and also still the 16mm piston pin!!! I.e. for TS 1 with 63 mm stroke (or even 65 mm).

Specialties Lambretta:

Often Lambretta crankshafts are very different, since there are very many different manufacturers. So the excentric pin for the 22mm (big end) will not fit the 22.9mm (big end) crankshaft. Please make sure you measure the width of the crankshafts halves. Most of the time the Flywheel housing has to be set out a little bit to accommodate the wider crankshaft. Big end pin length 41.5 mm - 12.6 mm for each crankshaft half - 16.3 mm in the middle for connecting rod, bearing and thrust washers. A standard crankshafts big end is 40.0 to max. 40.5 mm long. <== Measure!!!! Another connecting rod has to be used, since these big ends have 24mm diameter.

Modification of your crankshaft (16mm piston bolt / 110mm original connecting rod):

big end pin 115 EURO
disassembly, assembly, alignment and balancing of crankshaft from 50 EURO
Modification of the connecting rod about 50 EURO

Vespa T5
We now offer excentric big end pins for the Vespa T5 (see Onlineshop). The stroke is increased from 52 mm to 56.5 mm on the T5 crankshaft. A different connecting rod has to be used for this application. It is 110 mm long, 5 mm longer than stock. To compensate for the increased stroke and connecting rod length a 6 mm spacer is installed at the bottom of the cylinder. (see Onlineshop). After some modification the crankshafts can still be used with rotary slide valve intake.

Modification of your crankshaft – rotary slide valve :

big end pin 115 EURO
disassembly, assembly, alignment and balancing of crankshaft 50 EURO
special connecting rod, modified, including bearings and thrust washers 115 EURO
6 mm spacer aluminium 29 EURO

Vespa Smallframe
The Smallframe – excentric big end pins (see Onlineshop) have an excentricity of 1.25 mm. This increases the stroke from 51 mm to 53,5 mm. Similar to the T5 a different connecting rod has to be used, too, because the big end bearing does not fit on the new pin. This new connecting rod is available with a 15 and 16 mm piston pin. It is 97 mm long (stock length). For membrane intake ONLY!!!

Modification of your crankshaft :

Big end pin 115 EURO
disassembly, assembly, alignment and balancing of crankshaft 50 EURO
crankshaft halves modification (inside) 30 EURO
special connecting rod, modified, including bearings and thrust washers 115 EURO

Vespa PX 57 mm stroke / 22 mm big end
We now offer the excentric pins for Vespa crankshafts with 57mm and 22mm big end. (see Onlineshop) This increases the stroke to 59.5mm this is especially interesting for HPC crankshafts. We use a 110mm connecting rod for PX 200 and a 105mm connecting rod for PX 125 crankshafts. Now for the real special! It is also possible to reduce the stroke with an excentric pin. So the stroke is reduced from 57mm to 54.5mm and this makes a perfect fit for a liquid cooled Polini Cylinder Kit!!!! Membrane Intake ONLY!!!

Modification of your crankshaft:
big end pin 115 EURO
disassembly, assembly, alignment and balancing of crankshaft 50 EURO
special connecting rod, modified, including bearings and thrust washers 95 EURO

Vespa PX 60 mm / with 20 mm big end
Also new in our program are excentric pins for 60mm Mazzuchelli PX long stroke crankshafts (see Onlineshop). This increases the stroke from 60 mm to 62.5 mm. For Membrane Intake ONLY!!! At least a 1 mm spacer has to be used at the bottom of the cylinder, otherwise the upper piston ring will jump out the upper end of the bore.

Modification of your crankshaft:
big end pin 115 EURO
disassembly, assembly, alignment and balancing of crankshaft 50 EURO
special connecting rod, modified, including bearings and thrust washers 95 EURO

Custom built excentric big end pins

It is possible to build custom pins for different crankshafts. This requires the crankshaft to be disassembled so that we can determine all the measurements. The pins are rough turned in a high quality case hardened steel, then tempered and finally they are lapped to the final measurements.

Allow circa 8 - 12 weeks

Custom build of a big end pin :
Disassembly of crankshaft, measuring and creating blueprint 150 EURO
big end pin 150 EURO
special connecting rod, modified, including bearings and thrust washers circa 100 EURO
assembly, alignment and balancing of crankshaft 40 EURO

Flow optimized crankshaft for membrane intake

We can modify your crankshaft to optimize gas flow, fine balance and polish it. The so modified crankshaft offers a much improved flow especially in the intake area, where an unmodified crankshaft disturbs the gas flow and not enough gas can pass through. Also new crankshafts can be modified. This modification usually only works on a Vespa in combination with a membrane intake. The modification of the T5 crankshaft is a bit more complicated. The pockets on the inside of the crankshaft are closed (welded), which means the crankshaft is disassembled, modified and later assembled again. Smallframe crankshafts can also be flow optimized.

Modification of your crankshaft :
PX and Smallframe 65 EURO
T5 130 EURO

Disassembly, Assembly, Alignment and Balancing of Crankshafts
Repairing and modifying a crankshaft requires the disassembly and reassembly of a crankshaft. I.e. a different connecting rod may be required for extreme motor tuning because of the length and/or the piston bolt diameter. If the big end bearing or connecting rod are damaged the crankshaft also has to be disassembled and a new connecting rod kit (big end pin, bearing, washers and connecting rod) is installed. Of course the crankshaft is aligned and balanced after that.

We have build ONE a scootermatic 50 cc crank from TWO cranks. We can take a Malossi Piaggio MHR and a PGO crank. On varioside there is the Malossi crank side - on the flywheelside the PGO part (see pictures).

Disassembly, assembly, alignment and balancing your crankshaft from 50 EURO

Crankshaft alignment
Sometimes the crankshaft halves twist out of alignment. This can be caused by the frequent load of daily use or by seizures. If for example the Pick-Up scratches on the inner side of the flywheel you can assume that the crankshaft is misaligned. The crankshaft now slowly but surely destroys the bearings with its wobbling and twisting. We realign the crankshaft halves on a special alignment tool. If necessary the crankshaft can be disassembled and for reassembly and lasting alignment the big end pin is glued in with a special Loctite product.

Crankshaft alignment from 25 EURO

Static Balancing of Crankshafts
If material is removed from a crankshaft (i.e. to change inlet timing) an imbalance is caused that can have strong negative effects. Often this is already noticeable even at medium rpm. But also some brand new crankshafts (i.e. long stroke PX 200 and PX 125 crankshafts) have a strong imbalance from stock. This is really sad, but unfortunately the truth. We inspect the crankshafts on a special balancing tool and remove material to balance them, so that they run smoothly.

ALL Vespa crankshafts that you buy from us are inspected and balanced at NO EXTRA CHARGE!!

Static balancing of a crankshaft from 20 EURO

Its possible to balance cranks including very heavy wolfram parts. Therefor we have to bore holes on the right place, where extra spindeld wolfram pins pressed in.

Balancing with wolfram pins from 150 EURO

Repair woodruff key groove
If the groove for the woodruff key on the flywheel side is damaged (locks the flywheel or respectively ignition timing), we can simply repair this by welding a permanent boss (replacing the woodruff key) on the crankshaft. Unfortunately this is NOT possible for the clutch side.

Repair woodruff key groove 25 EURO