8.1 OTTOPUNTOUNO CNC Brake Master Cylinder Ø11 mm – Black Edition for Vespa PK S/XL1
Modern braking technology, high-quality CNC machining, and seamless integration into the original Vespa handlebars. With the black 8.1 OTTOPUNTOUNO brake master cylinder, the Vespa PK S or PK XL1 can be converted to a fully hydraulic disc brake system—without any time-consuming drilling or milling on the handlebars.
The master cylinder, manufactured in Italy, is mounted beneath the lower handlebar section. In addition to the brake pump, the set also includes a matching CNC clutch lever. This results in a visually harmonious combination of brake and clutch levers.
The advantages at a glance
- Black Edition: Sporty black lever design
- CNC-machined: Precision-engineered from aluminum, Made in Italy
- Ø11 mm brake piston: High hydraulic leverage with pleasantly low hand force
- No handlebar modification required: Mounts to the original PK S/XL1 lower handlebar section
- Matching lever set: CNC brake levers and matching clutch lever
- Versatile: Compatible with two- and four-piston calipers designed for fully hydraulic operation
Ø11 mm – powerful and easily modulated braking performance
The piston diameter of the master cylinder significantly influences the hydraulic ratio and thus the required lever force.
With its 11-mm master cylinder piston, the 8.1 OTTOPUNTOUNO master cylinder offers a high hydraulic ratio. When paired with a suitable brake caliper, this allows for high brake pressure to be generated with comparatively low hand force.
This is particularly advantageous for modern four-piston calipers. However, a powerful and easily controllable braking system can also be built using suitable two-piston calipers.
The actual braking performance depends on the brake caliper used, its piston diameters, the lever geometry, and the entire braking system.
Ideal for converting from semi-hydraulic to fully hydraulic systems
A particularly interesting application is the conversion of existing partially hydraulic disc brake systems, such as those with a cable-operated Grimeca master cylinder.
The commonly used Grimeca master cylinder has a piston diameter of 13 mm. With the 11-mm master cylinder of the OTTOPUNTOUNO brake pump, the hydraulic ratio changes to provide higher brake pressure while maintaining the same actuation force on the master cylinder piston.
The smaller master cylinder piston requires a correspondingly longer piston stroke. The result can be a significantly lower amount of hand force required, provided the master cylinder and brake caliper are properly matched.
The 8.1 also offers a high-quality solution for handlebar-mounted actuation when converting from drum brakes to disc brakes. The remaining brake components required for this must be purchased separately.
Black CNC levers for a cohesive look
The Black Edition complements the technically advanced master cylinder with a sporty, black lever design.
The included clutch lever is designed to match the brake lever. This creates a uniform look on the handlebars without having to combine different lever shapes or finishes.
The brake lever also features an adjustment option for the actuation point or lever reach.
Technical Specifications
| Feature |
Model |
| Manufacturer | 8.1 OTTOPUNTOUNO |
| Component | Hydraulic master cylinder |
| Model | Black Edition |
| Material | CNC-machined aluminum |
| Piston diameter | Ø11 mm |
| Brake Actuation | Fully hydraulic |
| Mounting position | Lower handlebar section, right |
| Brake lever | CNC-machined, black |
| Clutch lever | CNC-machined, compatible |
| Brake line connection | M10 × 1 hollow screw |
| Country of manufacture | Italy |
| Compatible vehicles | Vespa PK S / PK XL1 |
Package Contents
- 8.1 OTTOPUNTOUNO CNC Master Cylinder Ø11 mm, Black Edition
- Compatible CNC Brake Lever
- Compatible CNC clutch lever
- Required mounting and actuation components for handlebar installation
Not included: Hydraulic brake line, brake caliper, and other components of a complete disc brake system.
Installation Instructions
The brake master cylinder is designed for installation on the original lower handlebar section of the Vespa PK S and PK XL1. No modification of the handlebar—such as drilling or milling—is required for the intended installation.
The brake line must be selected to match the fork and brake system used and routed properly. After installation, the hydraulic system must be completely bled.
Before putting the system into service, carefully check the tightness of all connections, the lever travel, the free play at full steering lock, and the operation of the entire brake system.
Frequently Asked Questions (FAQ)
Does the original PK handlebar need to be modified?
No. The 8.1 OTTOPUNTOUNO brake master cylinder has been designed for installation on the original lower handlebar section of the Vespa PK S and PK XL1. No extensive drilling or milling is required for the intended installation.
Can I retrofit an existing semi-hydraulic disc brake?
Yes. The brake pump is suitable for converting to a fully hydraulic brake system, provided the existing brake caliper is compatible with the 11-mm master cylinder. The cable-operated master cylinder solution is replaced by a fully hydraulic system.
Is the master cylinder suitable for four-piston calipers?
Yes, the 11-mm master cylinder is particularly well-suited for appropriately designed four-piston calipers. Exact compatibility depends on the piston diameters and the required fluid volume of the caliper.
Is the brake line included in the scope of delivery?
No. The hydraulic brake line must be ordered separately. This allows you to select the length and connection type that match the fork and brake system being used.
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