The Marzocchi Bomber DJ [paid link] is a high-performance suspension fork designed for aggressive riding styles, particularly in dirt jump and street biking. Proper maintenance is crucial to ensure optimal performance, longevity, and smooth handling on tough terrain. In this guide, we will cover everything you need to know about servicing the Bomber DJ [paid link], from installation and adjustments to troubleshooting common issues and customizing the fork for peak [paid link] performance.

Tools Required

• Marzocchi Bomber DJ service kit
• 5mm, 6mm, and 8mm Allen wrenches [paid link]
• T25 Torx wrench [paid link]
• Torque wrench [paid link]
• Suspension oil (recommended by Marzocchi)
• Rags and cleaning supplies
• Shock pump
• Needle nose pliers
• Plastic spatula or scraper
• Fork grease

Installation of Bomber DJ Suspension Fork

Installing the Marzocchi Bomber DJ suspension fork is relatively straightforward but requires precision. Here’s a step-by-step guide to ensure a proper installation:

1. Prepare the Frame: Make sure your bike’s head tube and headset are in proper working condition. Clean any dirt or debris from the area to prevent contamination.
2. Insert the Fork Steerer: Carefully insert the fork steerer tube into the headset, ensuring it aligns properly. If your fork has a star nut or compression plug, install it before inserting the fork.
3. Attach the Fork to the Frame: Tighten the headset top cap using a torque wrench [paid link] to ensure the correct preload is applied. The recommended torque is typically around 5-7 Nm, but refer to Marzocchi’s manual for precise values.
4. Install the Front Wheel: Slide the front wheel into the fork dropouts, ensuring the wheel is centered and securely fastened.
5. Attach the Brake System: If you’re using a disc brake, ensure that the brake caliper is mounted correctly to the fork and that the rotor is properly aligned.

Adjustment for Optimal Performance

Once installed, the Bomber DJ suspension fork may need some initial adjustments to suit your riding style and weight. These adjustments will enhance the performance, ensuring the fork reacts optimally to different terrains.

Compression and Rebound Settings

The Bomber DJ features adjustable compression and rebound settings. Compression controls the fork’s resistance to impacts, while rebound controls how quickly the fork returns to its original position after compression.

1. Compression Setting: Adjust the compression knob to control the firmness of the fork. For dirt jumps, you may want a firmer setting, while softer settings can be more suitable for technical riding or downhill.
2. Rebound Setting: Adjust the rebound knob to control how fast the fork returns after an impact. A faster rebound helps with quick terrain response, while slower rebound is better for smoother and more controlled rides.

Air Pressure

The Bomber DJ fork comes with an air spring system. Adjusting the air pressure is critical for fine-tuning the fork’s feel.

1. Determine the Correct Pressure: Check the manufacturer’s recommended air pressure for your weight. This can typically be found in the Marzocchi manual or online.
2. Using a Shock Pump: Use a shock pump to adjust the air pressure through the valve located on the fork leg. Adjustments should be made in small increments, checking the fork’s sag (the amount the fork compresses under rider weight) to ensure it’s within the recommended range.

Fork Sag

Sag is the amount the suspension compresses when you sit on the bike. It’s crucial for comfort and performance.

1. Check Sag: Stand next to the bike and press down on the handlebars to compress the fork, then measure how far the fork compresses. Ideally, you want around 20-30% of the fork’s total travel as sag for dirt jump applications.

Maintenance of the Bomber DJ Suspension Fork

Regular maintenance of your Bomber DJ fork is essential to keep it performing at its best. Here’s how to maintain it:

Cleaning the Fork

After every ride, it’s a good idea to clean the fork to prevent dirt, grime, and moisture from affecting its performance.

1. Wipe Down the Fork: Use a clean rag to wipe the stanchions and lowers. Be sure to remove any dirt or debris from the seals.
2. Clean the Fork Seals: Dirt can easily get trapped in the fork seals, so carefully clean them using a damp cloth. Use a plastic spatula to gently scrape any grime around the seals.
3. Check for Leaks: After cleaning, inspect the fork for any oil leaks. If oil is leaking from the seals, they may need replacement.

Oil Change and Fork Service

Changing the suspension oil regularly is key to keeping the Bomber DJ fork operating smoothly.

1. Disassemble the Fork: Remove the wheel and the fork from the bike. Use an Allen wrench [paid link] and Torx wrench [paid link] to remove the bolts securing the fork.
2. Drain Old Oil: Carefully remove the lowers and drain the old suspension oil from the fork legs. Ensure all of the old oil is removed to prevent contamination.
3. Apply Fresh Oil: Follow the manufacturer’s guidelines for the correct oil type and quantity. Use a clean syringe to inject the oil into the fork legs. Ensure the oil is evenly distributed for consistent performance.
4. Reassemble the Fork: Once the oil has been added, reassemble the fork, ensuring all bolts are tightened to the specified torque values.

Seal Replacement

Fork seals are critical to keeping the fork’s internals protected. If you notice leaking or poor performance, it may be time to replace the seals.

1. Remove the Lowers: As with an oil change, begin by disassembling the fork.
2. Replace the Seals: Remove the old seals and replace them with new ones. Lubricate the new seals with suspension grease to ensure a smooth fit.
3. Reassemble the Fork: Carefully reassemble the fork and ensure it is properly lubricated and sealed.

Troubleshooting Common Issues

Fork Sticking or Not Moving Smoothly

If your fork is not moving smoothly, it could be due to contamination in the seals or a lack of lubrication.

1. Clean and Lubricate: Check for dirt in the seals and clean them thoroughly. Apply a thin layer of fork grease to the moving parts.
2. Check Air Pressure: If the fork feels overly stiff, check the air pressure. A low air pressure can cause the fork to feel sluggish, while too much pressure can make it feel harsh.

No Rebound or Too Slow

If the rebound is either too slow or non-existent, the issue may lie with the internal damper.

1. Check Damper Setting: Verify that the rebound setting is properly adjusted.
2. Oil Change: An oil change may be necessary if the fork feels like it is not returning to its original position smoothly.

Customization and Optimization for Better Performance

The Bomber DJ fork is highly customizable, allowing you to optimize it for different riding conditions and preferences. Consider the following upgrades to enhance your fork’s performance:

Upgrade the Springs

Swapping out the air spring for a coil spring can provide a more consistent feel, especially in aggressive riding styles like dirt jumping and slopestyle. Coil springs tend to be more durable and can be tuned by changing the spring rate.

Install a Larger Air Volume Spacer

Air volume spacers can be used to adjust the progression of the suspension, making it more responsive in the initial part of the stroke. Adding or removing spacers can help tailor the fork to your specific riding style.

Compatibility with Other Drivetrain Components

The Marzocchi Bomber DJ fork is designed for use with a wide variety of bike setups, but it’s essential to check for compatibility with other components, particularly the front wheel and brake system. Ensure that the fork’s axle type and the brake mount match the requirements of your bike. For instance, check whether your fork is compatible with your disc brake rotor size or if an adapter is necessary.

The Bomber DJ works best with a tapered headset and is designed for 20mm through-axle wheels, which can sometimes limit compatibility with standard quick-release systems. Before making any changes, confirm that the fork matches your bike’s geometry and component specifications.