SIP PREMIUM 62 stroke crankshaft, connecting rod 127mm for VMC Crono, keyed - 45021731

High-end crankshaft for Vespa Largeframe models. More stroke and top quality for high-torque everyday engines.

The crankshaft, along with the cylinder, is the heart of every engine. It is one of the most stressed parts. The conversion from stroke to rotary motion places the highest demands on quality and workmanship. The crankshaft must be well balanced to reduce vibrations. Oscillating masses must be low to sustain engine performance. The lower connecting rod bearing rotates at engine speed, is lubricated by the two-stroke mixture, and must absorb the load of the piston's change of direction twice per revolution. The crankpin, which connects the two crank branches and the connecting rod, must be compressed precisely to the right point. If the pressure is too low, the cranks will twist relative to each other. To ensure that a sufficient amount of mixture reaches the lower connecting rod bearing for lubrication, the lower connecting rod eye must be equipped with lubrication slots.

Particularly smooth operation

High-quality materials and workmanship

Available with polished forged connecting rod

SIP crankshafts

SIP 's crankshaft line is manufactured in Italy and meets the highest crankshaft standards. Special attention has been paid to quality and sophisticated design features. Each crankshaft is balanced according to the stroke, connecting rod length, and scooter model.

Crankshafts with particularly long connecting rods, designed for the heavier 72 mm pistons or requiring more counterweight due to a particularly long stroke, are equipped with tungsten weights.

The trees are available in two versions:

The "Premium" models are supplied with a high-quality connecting rod in standard execution, i.e. with an untreated surface. The connecting rod is equipped with cooling slots and bearing bores.

The "Performance" crankshafts feature a high-quality polished connecting rod. Polishing refines the surface, resulting in a denser, more stable structure, making the connecting rod more durable. The polished surface also ensures less turbulence. The polished connecting rods are further optimized for weight. Their lateral profile is more aerodynamic, and they have been redesigned in the lower bearing area for even better cooling of the connecting rod bearing.

The PX 60 mm long stroke crankshaft

At 60 mm, the long-stroke crankshaft for Vespa Largeframe models has a stroke 3 mm longer than the original crankshaft. This increases displacement by approximately 5%. The improved stroke-to-bore ratio not only increases performance, but also torque in particular.

This crankshaft was designed to be particularly suitable for high-torque engines and everyday tuning. The 60 mm stroke can be accommodated in the original crankcase; SIP 60 mm crankshafts fit without adjustment.

The distribution disc valve

Rotary valve crankshafts are available with two timing variants:

115°/4°: very close to the original timing. Particularly suitable for light "road" tuning.

125°/-5°: with an intake valve timing extended by approximately 20°. The extended timing is ideal for sporty tuning.

At the same time, the timing remains within a range that's still very suitable for everyday use. Engine performance isn't lost at low revs and can be easily fine-tuned. Backfire from the crankcase remains low. The contour of the control cheek has been designed to allow for the smoothest possible throttle entry.

Furthermore, this type of cheek allows for particularly effective balancing of the crankshaft and therefore particularly smooth operation of the engine.

The lengths of the connecting rods

We supply long stroke crankshafts with the following connecting rod lengths:

105 mm: for 125-150 cc largeframe models

110 mm: for the 200cc class

127 mm: for the M244/M232 QUATTRINI.

The extra millimeter compared to the original length of the Quattrini connecting rod allows for adjustment of the timing. Two small tungsten weights have been mounted here for perfect balance with the Quattrini piston.

Note: The SIP rotary vane crankshaft cheek has a particularly precise fit for smooth engine operation. Aftermarket housings or defective rotating contact surfaces in the housing may cause contact between the crankshaft and the housing. Check dimensional accuracy before installation.

Conclusions: The ideal crankshaft for delicate and reliable tuning, from the improved original engine to the Malossi Sport with box exhaust and 20 HP suitable for tourism.

The best configuration - our SIP -TIP:

When replacing the crankshaft, always replace the bearing and oil seal as well. For example, item nos. M6615466 and M6617236.

Compensate for the extra stroke with a 1.5mm head gasket or use a cylinder designed for a 60mm stroke. 15060000.

The new reinforced Woodruff keys are always a useful addition: Item No. 87059200

The perfect connection between the crankshaft and the clutch, for all Vespa largeframe models.

PIAGGIO designed these engines with a cylindrical flange, a spring washer, and an M12 nut holding the crankshaft and clutch together. Generally, this arrangement works quite well in a standard engine. Today, however, this proven configuration is unable to reliably transmit the power that has become achievable. To address this problem, we can now present a solution that offers the following advantages:

Pinion-teeth interlock connection.

Ease of assembly.

Solid and long-lasting connection, for all mileages and power ratings.

We now offer a range of crankshafts and clutches featuring interlocking connections that are extremely robust and stable in operation. This technology has already proven its worth in the design of our BFA 306 engine. These high-performance engines are capable of delivering power outputs of up to 72 hp! When dismantling such an engine after operation, the clutch could be removed by hand once the retaining nut was loosened, without any wear! These findings led us to transfer this advanced idea to more conventional engine casings, setups, and clutch concepts.

Without woodruff key but with M14 fixing nut thread.

All SIP crankshafts and clutches featuring this interlocking connection are compatible with each other. With this system, the components are locked together and held in place by the M14 retaining nut, eliminating the need for a Woodruff key. In the original engine crankcases, a 3.5 mm thick spacer disc must be placed between the clutch and the bearing, while in our SIP BFA crankcases, a thinner 2.5 mm spacer disc is used.

Attention: The oil pump gear cannot be mounted.

Conclusions: A complete solution, which eliminates once and for all one of the weakest links in the transmission of Vespa largeframe engines.