1. Product Overview
The OHLINS RWU (Right Way Up) Upright Front Fork FS624G is a high-performance suspension system meticulously engineered for the KAWASAKI ZEPHYR1100. This model represents a complete redesign, focusing on essential functions and a clean aesthetic while incorporating advanced suspension technology. It aims to provide superior handling stability and rider comfort by minimizing friction and offering precise damping control across various riding conditions.
This front fork features a low-friction design and a highly rigid structure, ensuring smooth operation and consistent performance. It integrates a one-way cartridge system (NIX25) for independent compression and rebound damping adjustments, allowing riders to fine-tune their suspension settings with precision.
Image: OHLINS RWU Upright Front Forks, showcasing both gold and black color options.
2. Specifications
Key Features:
- Compatible Vehicle: KAWASAKI ZEPHYR1100
- Compression Damping Adjustment: 20 steps
- Rebound Damping Adjustment: 20 steps
- Preload Adjustment: Up to 15mm (without affecting stroke length)
- Exterior Finish: High-quality alumite (gold or black)
- Top Cap & Bottom Bracket Finish: Titanium gray
- Caliper Bracket Material: 7075 Aluminum (machined)
- Axle Compatibility: Up to Φ25 axle shafts
- Optional Spring Rates: 8 types, ranging from 7.5-11.0 N-mm
General Specifications:
| Attribute | Value |
|---|---|
| Manufacturer | OHLINS |
| Brand | OHLINS |
| Model Name | FS624G |
| Product Model Number | FS624G |
| Product Weight | 10 Kilograms |
| Package Dimensions | 140 x 30 x 30 cm |
| ASIN | B01IEJ8186 |
| First Available Date | July 13, 2016 |
3. Setup and Installation
Installation of the OHLINS RWU Front Fork FS624G should be performed by a qualified technician with appropriate tools and knowledge of motorcycle suspension systems. Incorrect installation can lead to serious injury or damage to the motorcycle.
Important Compatibility Notes:
- The OHLINS RWU Front Fork FS624G is not compatible with the KAWASAKI ZEPHYR1100RS model.
- Installation may require extending the brake hose by approximately 5 cm. Verify brake hose length and routing after installation.
- For vehicles equipped with standard 18-inch wheels, an aftermarket handlebar post may be necessary to achieve proper offset adjustment.
Always refer to your motorcycle's service manual for specific torque values and procedures related to front fork removal and installation. Ensure all fasteners are tightened to the manufacturer's specifications.
Image: A KAWASAKI ZEPHYR1100 motorcycle equipped with the OHLINS RWU Front Fork, demonstrating the installed appearance.
4. Operation and Adjustments
The OHLINS RWU Front Fork FS624G offers comprehensive adjustability to tailor the suspension performance to your riding style, weight, and road conditions. All adjustments are conveniently located on the top caps of the fork legs.
Damping Adjustments:
- Compression Damping: Controls the speed at which the fork compresses. Adjustments are made via the designated clicker on the top cap (typically marked 'COMP' or with a 'C'). Turning clockwise increases damping (firmer), and counter-clockwise decreases damping (softer).
- Rebound Damping: Controls the speed at which the fork extends after compression. Adjustments are made via the designated clicker on the top cap (typically marked 'REB' or with an 'R'). Turning clockwise increases damping (slower rebound), and counter-clockwise decreases damping (faster rebound).
Both compression and rebound damping offer 20 distinct adjustment steps, allowing for precise tuning.
Preload Adjustment:
Spring preload adjusts the initial compression of the fork spring, affecting ride height and sag. The preload adjuster is located on the top cap and allows for up to 15mm of adjustment. Increasing preload will raise the front end and reduce sag, while decreasing preload will lower the front end and increase sag. This adjustment does not affect the fork's stroke length.
Image: Detailed view of the OHLINS RWU Front Fork top caps, highlighting the compression, rebound, and preload adjustment mechanisms.
Always make small, incremental adjustments and test the changes in a safe environment. Keep a record of your settings to easily revert to a previous setup if needed.
5. Component Details
The OHLINS RWU Front Fork FS624G is constructed with several key components designed for optimal performance and durability:
- Cartridge System: Utilizes the NIX25 one-way cartridge, a core technology previously proven in inverted forks, now adapted for upright fork applications. This system ensures completely independent compression and rebound damping circuits.
- Top Cap: Features a new structure where the cap bolt does not cause stroke variation during initial adjustments. The design is inspired by inverted forks and scaled for the Φ43 inner tube diameter.
- Outer Tube: Redesigned in the axle bracket area to achieve a deeper engagement length, contributing to smoother operation and high rigidity. Dust seals with garter springs are installed between the inner tube and dust seal for enhanced dust resistance and durability.
- Inner Tube: Developed with a low-friction specification, originally for inverted forks. An additional polishing process with ultra-fine compounds further reduces friction compared to conventional products.
- Bottom Bracket: The adoption of the new cartridge system eliminates the need for a base valve, centralizing all adjustments to the top cap for intuitive operation. Forged and machined parts enhance rigidity around the axle.
- Spring & Guide: Employs springs designed for inverted forks to meet a wide range of spring rate requirements. A newly designed resin spring guide prevents contact with the inner tube, reducing friction, improving quietness, and contributing to better oil degradation resistance.
- Top-Out Spring: The top-out spring mechanism, previously limited by the cylinder and inner tube end, has been moved to the cartridge side, resulting in softer and smoother top-out characteristics.
- Finish Work: High-grade alumite finish is available in gold and black. The top cap and bottom bracket feature a titanium gray finish, with laser-engraved logos for a premium appearance.
Image: Close-up of the gold OHLINS RWU Front Fork's bottom bracket and caliper mounting points, showcasing the machined 7075 aluminum construction.
Image: Close-up of the black OHLINS RWU Front Fork's bottom bracket and caliper mounting points, highlighting the robust design.
6. Maintenance
Regular maintenance is crucial for ensuring the longevity and optimal performance of your OHLINS RWU Front Fork. Adhere to the following general guidelines:
- Regular Cleaning: Keep the outer tubes and inner tubes clean from dirt, dust, and road grime. Use a soft cloth and mild cleaning solution. Avoid abrasive cleaners.
- Inspect Seals: Periodically check the fork seals for any signs of leakage or damage. Leaking seals should be replaced promptly by a qualified technician.
- Fork Oil Replacement: Fork oil degrades over time and with use. Consult an OHLINS service center or a qualified mechanic for recommended service intervals for fork oil replacement and internal inspection.
- Fastener Torque: Regularly check the torque of all mounting bolts and fasteners, including axle clamps and caliper mounts, to ensure they are within specified limits.
- Professional Servicing: For any internal repairs, seal replacements, or major adjustments, it is highly recommended to seek professional servicing from an authorized OHLINS service center or a certified motorcycle suspension specialist.
7. Troubleshooting
This section provides general guidance for common issues. For complex problems, always consult a professional.
Common Issues and Solutions:
- Excessive Harshness/Stiffness:
Possible Causes: Too much compression damping, too much spring preload, incorrect spring rate for rider weight.
Solutions: Reduce compression damping (turn counter-clockwise), reduce spring preload, consider a softer spring rate if necessary. - Excessive Softness/Bottoming Out:
Possible Causes: Too little compression damping, too little spring preload, incorrect spring rate for rider weight.
Solutions: Increase compression damping (turn clockwise), increase spring preload, consider a stiffer spring rate if necessary. - Slow Rebound (Fork packs down):
Possible Causes: Too much rebound damping.
Solutions: Reduce rebound damping (turn counter-clockwise). - Fast Rebound (Fork tops out too quickly):
Possible Causes: Too little rebound damping.
Solutions: Increase rebound damping (turn clockwise). - Oil Leakage from Seals:
Possible Causes: Damaged or worn fork seals, dirt trapped under seals.
Solutions: Clean seals carefully with a seal cleaner tool. If leakage persists, seals require replacement by a professional.
If you are unable to resolve an issue, or if you suspect internal damage, contact an authorized OHLINS service center for assistance.
8. Warranty and Support
For information regarding product warranty, please refer to the warranty documentation provided with your OHLINS product at the time of purchase. Warranty terms and conditions may vary by region and retailer.
For technical support, spare parts, or professional servicing, please contact your authorized OHLINS dealer or visit the official OHLINS website for a list of service centers in your area. Always provide your product model (FS624G) and purchase details when seeking support.
