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DEXTER RACING Item number: DEX110036
DEXTER RACING

Crankshaft - DEXTER RACING - Largeframe full cheek, 60 mm stroke, 105 mm connecting rod - Vespa PX125, PX150, Cosa 125/150, Sprint Veloce, GTR 125, TS 125, Super 150

Short facts Dexter Racing full cheek shaft 60/105

Full cheek shaft for diaphragm intake (housing/cylinder) - not for rotary valve
Stroke 60 mm (+3 mm compared to standard), connecting rod 105 mm, piston pin Ø 15 mm
Flow-optimized intake cheek + full-surface Lima cheek, approx. 1.9 kg total mass
Check compatibility: M12 pole wheel thread / SW19 pole wheel nut
Designed for greatly increased engine performance - stable in everyday operation
459,00 €*
available immediately
Shipping weight 1,9 kg
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Crankshaft - DEXTER RACING Largeframe full

cheek

60 mm / 105 mm CNC connecting rod - Vespa PX125/150, Sprint, GT/GTR, TS, Cosa 125/150

Full cheek racing crankshaft for largeframe small block (125/150) with diaphragm intake. The new design from Dexter Racing is perfect for fast street engines. The intake cheek is maximally streamlined and hardly shades the intake cross-section - ideal for large carburetors, LML 5-channel housings or PX125/150 engines converted to a reed valve. The closed Lima cheek increases the primary compression across the entire band; approx. 1.9 kg shaft mass, despite a very streamlined layout, results in powerful yet quiet running. Manufactured to a very high standard in a small series in Italy by Dexter Reacing - with a high-quality and durable CNC connecting rod. Shaft with counterweight and finely balanced.

Diaphragm inlet 60 mm stroke 105 mm CNC connecting rod Ø15 mm piston pin approx. 1.9 kg Flow-optimized

Advantages and area of application

Diaphragm-optimized intake: minimal cross-sectional shadow, high flow
Full cheek + equalizing inserts: better filling, smooth idling, powerful pull-through
60 mm long stroke increases displacement/scavenging - wide torque curve suitable for everyday use
Very good for box setups (e.g. BGM 177, Polini/Malossi/VMC 177-190) with long primary
Gear ratios 23-24/62 without problems; tends to be shorter with resonance systems (23/63)

Technical data

Stroke: 60 mm (small-block largeframe)
Connecting rod: 105 mm CNC, piston pin Ø 15 mm
Cheeks: Intake cheek flow-optimized, Lima cheek full-surface
Mass/balance: approx. 1.9 kg, weight/balance inserts
Bearings/Simmerrings: suitable for the small-block platform (select model-specific)

Important note - only for diaphragm intake

This crankshaft is only suitable for engines with a diaphragm intake system (on the housing or cylinder). It cannot be used in original rotary valve engines. For the conversion, the rotary valve surface must be deactivated/sealed and a suitable diaphragm support, carburetor and spacer concept must be provided.

Compatible vehicle models (Small-Block 125/150)

Vespa 150 Super - VBC1T from model no. 412374
Vespa 150 Sprint Veloce - VLB1T (SV) from model no. 294260
Vespa 125 TS - VNL3T from model no. 18139
Vespa P125X - VNX1T; P150S - VBX1T; P150X - VLX1T
Vespa PX125E - VNX2T; PX150E - VLX1T (PXE)
PX125E/PX150E Arcobaleno/Elestart - VNX2T/VLX1T (Arc/El)
PX125/150 (Lusso, MY, Disc, 2011)
Cosa 125/150

Test note: Only engines with pole wheel thread M12 and pole wheel nut width across flats 19 mm (not M11 / SW14).

LML Star / Star Deluxe 125/150 (Genuine Stella)
Motovespa PX derivatives 125/150 (e.g. Iris 125/150)

Requirement: Small-block crankcase 125/150 and pole wheel thread M12 / SW19.

T5 125 (other crankshaft type)
PX200 / Rally200 (big-block platform)
Standard rotary valve engines without diaphragm conversion

Practice & setup notes

"Power cruiser" box concept: 177-190 cc cylinder (BGM/Polini/Malossi/VMC), 28-30 mm carburetor, reed valve on housing, 60/105 shaft, high-quality box (e.g. BGM1010TR2). Result: very early, high torque and wide band.
Gear ratio: 23-24/62 without problems; with resonance systems rather 23/63.
Spacer tip: Preferably use head spacers instead of foot spacers - overflow angles remain favorable, the engine runs noticeably more powerful.
Pinch point/ignition: Pinch point typically 1.0-1.3 mm; adjust ignition timing and AFR to load/temperature.

Installation instructions

Only use in engines with diaphragm intake system; close/deactivate rotary valve surface.
Check freedom of movement of the 60 mm cheek in the housing; local reworking possible depending on housing/cylinder base.
Use suitable bearings/seal rings and pole wheel with M12 thread / SW19 nut.
For long stroke: Adjust timing/squeeze via spacers/seals; retighten all screw connections after initial run.

FAQ - Frequently asked questions about the DEXTER RACING 60/105 diaphragm crankshaft

Only if a diaphragm takes over the intake control. The shaft is designed exclusively for diaphragm intake (on the housing or cylinder). In the rotary valve, the DS surface must be opened/removed and converted to a diaphragm.
Yes, but the intake cheek is flow-optimized and hardly stands in the intake tract.
M12 pole wheel thread with pole wheel nut SW19 => standard for all specified models. If the pole wheel nut is M11 / SW14, the engine is still fitted with a crankshaft of the old model (Sprint). The shaft does not fit in this case.
Head spacers are preferable to foot spacers. This keeps the overflow angle advantageous and the engine runs more powerfully. Always match the trailing edge and ignition to the setup. As a rule, 18° is a perfect starting value (and often also the final value) for static ignitions. Please adjust the squish due to the long stroke with spacers. Depending on the cylinder manufacturer, between 1.00-1.60mm is usually OK.
For box setups (e.g. BGM 177 & Co.), 23-24/62 are no problem. For pure resonance setups, tend to choose shorter (max .23/63) - depending on cylinder/porting/tire circumference.
Yes. The flow-optimized intake cheek is ideal for LML 5-port or converted series PX125/150 housings. Large carburettors can be used with this crankshaft without significant cross-sectional shadows.
Designed for Ø15 mm piston pin. Select suitable pistons/needle bearings. The 105 mm connecting rod (same as standard length) results in high pre-compression, good for pressure over the usable speed range; note the spacer concept (head/foot) for timing and squish adjustment.
The higher moment of inertia supports the filling at low engine speeds and ensures smooth runningand powerful pulling power - particularly harmonious with high-torque box systems.
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