Use only on approved Stark Varg models
Clutch 1.0 User Manual
In depth user manual to your RARE Clutch 1.0.
1. Product Identification
Product Name: RARE Clutch – Digital Clutch SystemProduct
Role: Aftermarket / Third-Party Component for Electric Motorcycles
Compatible Vehicles: Stark Varg EX - Stark Varg MX - Stark Varg SM
2. Intended Use
The RARE Clutch is a digital clutch system designed exclusively as a component for use on compatible Stark Varg electric motorcycles.
It digitally processes the original throttle signal in combination with a sensor-based clutch lever to simulate clutch functionality and enable configurable throttle and engine behavior.
2.1 Permitted Use
2.2 Improper Use / Misuse
IMPORTANT
Any misuse may result in unintended acceleration, loss of control, serious injury, or death.
3. Safety Instructions
3.1 Safety Signal Words
| Signal Word | Meaning |
|---|---|
| DANGER | Hazardous situation resulting in death or serious injury |
| WARNING | Hazardous situation that could result in death or serious injury |
| CAUTION | Situation that may result in minor or moderate injury |
| NOTICE | Information related to equipment or property damage |
3.2 Symbols Used
| Symbol | Description |
|---|---|
| Safety warning |
 | Electrical connection |
 | Installation step |
 | App-related information |
3.3 General Safety Warnings
DANGER
Incorrect installation or configuration may cause unintended or unpredictable power delivery and loss of vehicle control.
WARNING
Installation by qualified personnel is strongly recommended.
Riding characteristics may change significantly after installation.
CAUTION
Disconnect from electricity before installation or service (Switch off the bike completely or disconnect the battery)
Always perform commissioning and functional tests before riding.
NOTICE
This product is NOT STREET LEGAL and NOT HOMOLOGATED for use on public roads.
The rider remains fully responsible for vehicle control at all times.
Read this manual completely before installation or operation.
Technical modifications on the system by the user are not permitted, unless approved by RARE GmbH.
4. Liability & Responsibility
RARE GmbH assumes no liability for damages resulting from:
Incorrect installation, improper or unintended use, violation of local laws or regulations, unauthorized modifications.
The user is solely responsible for:
Correct installation and configuration, compliance with national and regional regulations, safe operation of the motorcycle.
Installation of aftermarket components may affect warranty, homologation, or operating approval of the motorcycle.
5. Scope of Delivery
5.1 Package Contents
| Item | Description |
|---|---|
| 1 | RARE Control Unit (CU) with integrated speaker and (+ / −) buttons |
| 2 | RARE Clutch Lever including "Plus Tension Spring" |
| 3 | Handguard bolt (optional) |
| 4 | Plug-and-play wiring cables |
| 5 | Smartphone Application |
Not Included: Tools, smartphone, motorcycle components.
5.2 Part Overview
6. Technical Description
6.1 Functional Principle
The RARE Clutch with its Control Unit provides smooth, optimized and configurable throttle response while providing clutch engagement. The algorithm is set to simulate a response of a combustion engine, combined with the advantages of electric bikes.
Functional Flow:
All settings that affect ride behaviour are fully available to the user through the app.
6.2 Power Delivery with the RARE Clutch
Without a clutch, the full power range of the bike must be controlled solely with the right wrist, requiring extreme precision and wide hand motions. Achieving maximum output often demands a large twist of the throttle, which is difficult to perform quickly and compromises body position and the rider's ability to apply force effectively to the bike.
With the RARE Clutch, the rider can now decide when and how quickly power is released, as well as how smooth or aggressive the delivery should be. This can be adjusted dynamically while riding. The Control Unit algorithm allows the right hand to be less precise, enabling better focus on body position and force application, while the left index finger independently and quickly modulates clutch engagement.
6.3 Regenerative Braking: Recommended Settings
When using the RARE Clutch, it is recommended to set regenerative braking to 0%, especially for hill climbs. During uphill riding, regenerative braking causes the motorcycle to slow as soon as the throttle is released, which can interrupt riding flow and reduce built-up momentum when engaging the clutch.
On straight or downhill sections, regenerative braking can be adjusted according to rider preference. It can also be beneficial for controlled speed reduction and to help recharge the battery.
6.4 Plus Tension Spring
The Plus Tension Spring is located inside the lever pivot and is installed from the factory by default. It provides experienced riders with a firm, precise lever feel for aggressive riding, technical terrain, and advanced manoeuvres.
The Plus Tension Spring is intended for riders who prefer increased lever resistance and enhanced feedback. If hand fatigue or arm pump occurs, the spring can be removed without tools and without disassembling the lever.
NOTICE
Lever feel changes immediately after installing or removing the Plus Tension Spring. Familiarize yourself with the new lever feel before riding at speed or in demanding conditions.
7. Installation
Installer Skill Level: Experienced user or professional technician recommended
7.1 Installation Requirements
7.2 Installation Procedure
DANGER
Ensure the motorcycle is fully powered off before beginning installation.
Installation Steps:
6. Verify all connections and ensure correct cable routing.
WARNING
Make sure the CU plug connectors are not stressed or pinched when remounting the headlight.
8. Switch on your bike. Observe system startup behavior.
DANGER
Perform a functional test with the engine in neutral.
Test speaker output (audio feedback): Default: audio ON when clutch pulled, audio pitch based on throttle output
DANGER
While standing next to the bike, place it in a safe position and test clutch and throttle functionality:
• Test clutch lever actuation
• Verify smooth throttle response while stationary
• Do not ride if abnormal behavior is detected
8. Operation
8.1 Control Unit Buttons
| Button Input | Duration | Function |
|---|---|---|
| Short press (+ / −) | < 1 second | Adjust sound volume (0–100%) |
| Long press (+ / −) | > 1 second | Switch riding mode (1–5) |
9. Smartphone App
9.1 App Installation
Supported platforms: Android and iOS
Bluetooth required
Download ONLY the official "RARE Clutch" App from Google Play Store, iOS App Store or shop-rare.com
9.2 Custom Modes
Up to five individually configurable riding modes can be stored. Switch between modes with the buttons on the RARE Control Unit or using the smartphone app.
| Parameter | Description | Effect |
|---|---|---|
| Bite Point | Start of clutch engagement | Initial power delivery |
| End Point | Full clutch engagement | Maximum power threshold |
| Throttle Smoothness | Signal filtering | Reduced abrupt changes |
| Throttle Response | Throttle aggressiveness | Direct ↔ smooth |
| Flywheel Effect | Simulated inertia | Smoother RPM behavior |
| Sound Settings | Acoustic feedback | Rider feedback only |
NOTICE
Extreme settings may significantly alter riding behavior. Adjust gradually.
10. Recommended Presets
The following presets provide ready-to-use configurations for different riding styles and terrain. The Enduro Race preset is the default in all modes.
Enduro
Maximum control, good traction, smooth power delivery.
| Throttle Smoothness | 80% |
| Throttle Response | 22% |
| Flywheel Effect | 14% |
Characteristics: Smooth, gradual power increase. Slow decrease in RPM. Feels soft and predictable. Very easy to modulate, ideal for technical or relaxed riding.
Enduro Race (DEFAULT)
Realistic all-round performance. Our default preset, covering most riding situations.
| Throttle Smoothness | 60% |
| Throttle Response | 35% |
| Flywheel Effect | 20% |
Characteristics: Quick but controlled throttle response. Noticeable, but not aggressive RPM decrease. Mirrors the feel of modern Enduro bikes. Best choice for most riding situations.
2-Stroke Feel
Lively, responsive, lightweight engine feel.
| Throttle Smoothness | 40% |
| Throttle Response | 42% |
| Flywheel Effect | 38% |
Characteristics: Instantaneous throttle response. Very rapid RPM drop. Minimal trailing power. Classic 2-stroke powerband behavior.
Motocross (4-Stroke MX)
Explosive, fast and aggressive throttle, ideal for MX tracks.
| Throttle Smoothness | 40% |
| Throttle Response | 48% |
| Flywheel Effect | 32% |
Characteristics: Extremely fast torque build-up. Rapid RPM drop when rolling off the throttle. Clear on/off throttle feel. MX track performance, "race only" mode.
Hard Enduro
Maximum control at low speeds for extreme technical terrain.
| Throttle Smoothness | 88% |
| Throttle Response | 18% |
| Flywheel Effect | 10% |
Characteristics: Very soft, gradual throttle response. RPM remains steady, allowing smooth crawling. Bike "pulls through" obstacles predictably. Maximum traction. Perfect for steep climbs and technical sections.
11. Firmware & Calibration
11.1 Firmware Updates
Firmware updates enable users to access the latest features and new developments. Your RARE Control Unit can be updated using the RARE Clutch smartphone app.
WARNING
Interrupting a firmware update may cause permanent malfunction of the CU.
• Ensure stable Bluetooth connection
• Do not power off motorcycle or smartphone during update
• Check for automatic shutdown timers on your bike
11.2 Calibration
Start Calibration to ensure accurate clutch and throttle positions and correct system behavior.
Repeat the calibration if the behaviour of the clutch changes to unintended conditions.
12. Troubleshooting
| Issue | Possible Cause | Action |
|---|---|---|
| No throttle response | Connector not seated / Calibration needed | Check wiring / Perform calibration |
| Erratic behavior | Damaged cables | Inspect clutch system and replace broken parts |
| App connection failure | Bluetooth disabled / Another device connected | Enable Bluetooth / Disconnect other device |
| Clutch feels ON/OFF | Bite point and end point too close | Reset clutch mode to default |
| Metallic scratching sound | Plus Tension Spring contact | Rotate spring by hand until noise stops |
Contact customer support if issue persists.
13. Maintenance & Care
The design eliminates every aspect of maintenance and mechanical wear. No matter if temperature or altitude change and how many hours you ride, your setup stays consistent.
NOTICE
Do not direct a high-pressure washer or steam cleaner at the Control Unit.
14. Legal & Warranty
14.1 Software License
The RARE Clutch software, including the app, is licensed to the user for personal use only. All intellectual property rights in the software and app are retained by RARE GmbH. You may not copy, modify, reverse engineer, decompile, or distribute the software.
14.2 Warranty Coverage
RARE guarantees that its products are free from manufacturing defects in materials and workmanship at the time of delivery. The warranty covers defects that occur within two years from the date of delivery to the end consumer.
The warranty does not cover:
Detailed information: https://shop-rare.com/policies/refund-policy
14.3 Safety & Disclaimer
DANGER
After any crash or impact, inspect the RARE Clutch for damage before riding again. Check for broken parts, loose connectors, or cut/damaged cables.
If the motorcycle behaves unusually, stop riding immediately, inspect the clutch. Contact RARE support if necessary.
Riding with a damaged or malfunctioning clutch may result in loss of control and serious injury.
15. Contact
Manufacturer: RARE GmbH
Wengerstraße 10, 5621 St. Veit i.P., Austria
Website: https://shop-rare.com
Email: office@rare.com
© Rare GmbH. All rights reserved. Specifications subject to change without notice.
