Hand-finished EGIG PERFORMANCE replacement cylinder with a one-piece CHEB500 exhaust port for high-performance 220-cm³ small-frame engines.
The EGIG PERFORMANCE CHEB500 replacement cylinder is the sport-tuned single-exhaust version of the EGIG-220 cylinder design. With a 68 mm bore, designed for a 60 mm stroke and 117 mm connecting rod, and a hand-machined one-piece exhaust port, it forms the basis for high-performance 220 cm³ Vespa small-frame engines.
Unlike its Revo counterpart with a three-piece exhaust port, the CHEB500 features a single large exhaust port. At a 60 mm stroke, the valve timing is approximately 129° intake and 190° exhaust. This allows the cylinder to combine a sporty design with the crisp, direct characteristics of a one-piece exhaust port.
This item includes only the machined and coated cylinder body. The piston, cylinder head, diaphragm, intake manifold, gaskets, and other components must be selected to match the existing engine configuration.
EGIG PERFORMANCE CHEB500 220 cc Single Exhaust Port Hand-machined Nikasil Cylinder block only
The CHEB500 features a large, one-piece exhaust port. Unlike the three-piece Revo exhaust port, the exhaust flow is not routed through a main window and two side ports, but rather through a continuous exhaust opening.
The outlet contour is machined by hand to the CHEB500 specification. Machining takes place prior to the Nikasil coating, ensuring that the finished channel and window areas are also incorporated into the final coating process.
The CHEB500 and Revo use the same large-volume EGIG base design but differ in their exhaust layouts. The CHEB500 features a one-piece, hand-machined exhaust. The Revo, on the other hand, uses a three-piece exhaust system with two additional side exhausts.
| Feature | CHEB500 | Revo |
|---|---|---|
| Exhaust | One-piece | three-piece |
| Machining | Hand-finished | hand-finished |
| Control times at 60 mm stroke | approx. 129° / 190° | approx. 129° / 190° |
| Basic character | Sporty single-outlet design with direct and even power delivery | greater potential exhaust area and more focused on the upper RPM range |
| Target Application | Powerful street, touring, and sport engines | Performance-oriented resonance and racing engines |
The actual engine characteristics are not determined solely by the exhaust layout. The exhaust system, carburetor, diaphragm, ignition, compression ratio, crankshaft, and gear ratio all significantly influence the result.
In this configuration, the CHEB500 is designed for a crankshaft with a 60 mm stroke and a connecting rod 117 mm long. Combined with the 68-mm bore, this results in a displacement of approximately 220 cm³.
| Bore | Ø68 mm |
|---|---|
| Crankshaft stroke | 60 mm |
| Connecting rod length | 117 mm |
| Displacement | approx. 220 cm³ |
Different stroke or connecting rod combinations alter the cylinder position, valve timing, and compression edge. Such configurations must be individually adjusted using suitable spacers, gaskets, or by machining the components.
In the intended 220-cm³ configuration, the valve timing is approximately 129° at the intake valves and 190° at the exhaust valves.
This results in a calculated exhaust advance of about 30.5°. This design is clearly sporty and requires an exhaust system that matches the cylinder’s RPM range and airflow capacity.
The values listed are guidelines for the intended setup. Even minor changes to the cylinder head gasket, spacers, engine block, or crankshaft assembly can alter the actual valve timing.
The CHEB500 is made of aluminum and features a Nikasil coating as the running surface. Aluminum quickly dissipates the heat generated during combustion to the cooling fins, while the hard coating forms the running surface for the piston and piston rings.
The exhaust layout is machined manually prior to coating. As a result, the coated running surface already matches the final CHEB500 channel geometry.
The actual compression ratio is not determined by the cylinder alone. The piston, cylinder head, cylinder position, and squish edge must be considered as an integrated system.
With a properly designed piston and cylinder head, the guideline value for a squish edge of approximately 1.2 to 1.3 mm is around 12.5:1. This value must be verified on the specific engine and tuned to the fuel, ignition, exhaust system, and intended application.
The cylinder block features an eight-bolt pattern that accommodates both the M200 bolt pattern and the EGIG-250/300 configuration.
A 65 mm hole pattern is used at the exhaust outlet. Additionally, there is a third M8 thread in the center for attaching a correspondingly designed exhaust flange.
The cylinder head is not included in the scope of delivery and must be selected to match the piston used, the bore, and the desired compression ratio.
The mounting points and external dimensions of the EGIG cylinder design are intended for a PX125 cylinder cover. During assembly, the cover, head, and spark plug position must be checked together to ensure proper fit and sufficient clearance.
The EGIG cylinder concept is designed for high-performance diaphragm engines. It can be combined with a separately available Italkit 8-valve diaphragm and matching 30- or 34-mm intake manifolds.
Depending on the intake manifold used, the intake can be routed through the existing frame hole. The diaphragm block, intake manifold, and carburetor are not included with this replacement cylinder.
There are two centering pins at the base of the cylinder. This centering feature can only be used in conjunction with an EGIG/Fabbri engine housing designed for this purpose.
A 220-cm³ engine places high demands on the entire powertrain. The cylinder alone does not determine either performance or durability. The crankshaft, bearings, clutch, primary drive, transmission, ignition, and fuel system must be capable of withstanding the load.
| Vespa 125 Primavera | VMA2T, only with the corresponding EGIG/Fabbri engine configuration |
|---|---|
| Vespa 125 ET3 | VMB1T, only with corresponding EGIG/Fabbri engine configuration |
| Vespa PK125 | VMX1T, check engine base and peripherals |
|---|---|
| Vespa PK125 S | VMX5T, check engine base and peripherals |
| Vespa PK125 XL | VMX6T, Check Engine Base and Peripherals |
| Vespa PK125 ETS | VMS1T, Check engine base and peripherals |
The vehicle specification describes the possible small-frame base. The cylinder cannot be mounted on a stock PV, ET3, or PK125 engine without a comprehensively modified engine assembly.
| Manufacturer | EGIG PERFORMANCE |
|---|---|
| Series | CHEB500 |
| Component | Replacement cylinder / cylinder body |
| Displacement | 220 cm³ |
| Bore | Ø68 mm |
| Crankpin stroke | 60 mm |
| Connecting rod length | 117 mm |
| Cylinder material | Aluminum |
| Bearing surface | Nikasil coating |
| Exhaust design | One-piece, hand-finished |
| Flow-through time at 60 mm stroke | approx. 129° |
| Exhaust angle at 60 mm lift | approx. 190° |
| Calculated advance angle | approx. 30.5° |
| Exhaust port depth | 65 mm |
| Additional exhaust mounting | Center-mounted M8 thread |
| Stud configuration | M200 and EGIG 250/300, with eight studs |
| Cylinder head cover | Mounting points and dimensions for PX125 cylinder head |
| Centering | 2 centering pins on the cylinder base; can only be used with a compatible EGIG/Fabbri housing |
| Compatible with | Vespa PV125, ET3 125, and PK125 with corresponding engine configuration |
This item includes only the EGIG PERFORMANCE CHEB500 cylinder body.
The EGIG PERFORMANCE CHEB500 is a hand-machined 220-cm³ replacement cylinder for demanding Vespa small-frame projects. Its one-piece exhaust combines a clean, direct port layout with sporty valve timing of approximately 129°/190°.
Compared to the three-piece Revo exhaust, the CHEB500 relies on the characteristics of a large single-piece exhaust. This makes it ideal for riders who want to build a high-performance engine with smooth, predictable power delivery and a wide, adjustable operating range.
This requires a carefully planned complete system consisting of a 60-mm crankshaft, 117-mm connecting rod, matching piston and cylinder head, diaphragm intake, exhaust, ignition, and a robust drivetrain. Only the cylinder block is included in the delivery.
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