Maintaining your Marzocchi Bomber CR Coil [paid link] rear shock is essential for ensuring its performance, longevity, and overall functionality. One key maintenance task that riders should perform regularly is changing the shock oil. Fresh oil helps maintain smooth damping performance and reduces wear on internal components. In this guide, we’ll walk you through the entire process of performing a rear shock oil change for the Bomber CR Coil [paid link].

Tools Required

• 5mm and 6mm Allen wrenches [paid link]
• T25 Torx wrench [paid link]
• 17mm socket wrench
• Shock pump
• Marzocchi-specific oil (or equivalent shock oil)
• Oil drain pan
• Clean rags or paper towels
• Rubber gloves
• Syringe (for measuring oil)
• Suspension fluid syringe or fluid injector tool
• Torque wrench [paid link]
• Small pick or tool for removing seals
• Air compressor or shock pump for re-pressurization

Preparing the Bomber CR Coil for Oil Change

Before you begin the oil change process, it’s crucial to prepare the rear shock and your workspace. Follow these steps to ensure everything is set up correctly:

1. Remove the rear shock from the bike: Begin by removing the rear shock from your bike frame. Use the appropriate tools to remove the bolts and carefully detach the shock. Place it on a clean surface for the next steps.
2. Clean the shock area: Before working with the shock, clean any visible dirt or debris around the shock body. This prevents contamination from entering the shock during the process.
3. Work in a clean environment: Ensure your work environment is free of dirt, grease, or any contaminants that could affect the shock oil and internal components.

Draining the Old Oil

Draining the old oil is a vital step in the maintenance process. Old oil can cause poor damping performance if not replaced.

1. Remove the shock’s air can: Use a T25 Torx wrench [paid link] to remove the air can from the shock body. Carefully slide it off to expose the internal damping mechanism.
2. Drain the old oil: Hold the shock over an oil drain pan and allow the old oil to fully drain out. Be sure to let the oil drain completely before proceeding. This ensures that all contaminants and old oil are removed from the system.
3. Inspect the shock: While draining, take the time to inspect the shock body and components for any signs of damage or excessive wear. If you notice any issues, such as damaged seals or excessive wear on the shock shaft, you may need to replace those parts before continuing.

Cleaning the Internal Components

Proper cleaning is critical to ensure that your shock functions at its best after the oil change.

1. Clean the shock body: After draining the old oil, use a clean rag or paper towels to wipe down the shock body. Be thorough, as you need to remove any dirt or debris that may have accumulated inside.
2. Remove and clean the seals: Using a small pick or appropriate tool, gently remove the seals and any other components that come into contact with the oil. Clean them with a rag and inspect them for any signs of damage. If the seals appear worn or damaged, replace them with new ones.

Replacing the Oil

Now it’s time to add fresh oil into the shock. The Marzocchi Bomber CR Coil requires a specific type of oil to maintain its damping performance.

1. Measure the correct amount of oil: Refer to the Bomber CR Coil’s service manual for the exact amount of oil needed for your shock model. Use a syringe to measure the required amount of oil precisely.
2. Add the oil into the shock: Slowly pour the measured oil into the shock body through the air can section. Be sure to avoid introducing air bubbles during the filling process. Fill the shock until you reach the recommended oil level.
3. Reassemble the shock: Once the oil is in place, carefully reassemble the shock. Reinstall the seals, and ensure they are seated properly in their respective grooves. Make sure everything is correctly aligned.

Re-Pressurizing the Shock

After the oil change, you will need to re-pressurize the shock with air to restore its performance and responsiveness.

1. Install the shock back onto the bike: Before re-pressurizing the shock, reinstall it onto the bike frame and tighten the mounting bolts with the correct torque specifications using your torque wrench [paid link].
2. Set the correct air pressure: Use a shock pump to adjust the air pressure to the recommended levels. You may need to consult your bike’s manual or the Bomber CR Coil’s specific guide for the optimal air pressure range based on your weight, riding style, and shock settings.
3. Perform a sag test: After adjusting the air pressure, check the shock’s sag by sitting on the bike and compressing the shock. If the sag is not within the recommended range, adjust the air pressure again as necessary.

Troubleshooting Common Set-Up Issues

While performing the oil change, you might encounter some common issues. Here are some troubleshooting tips to address them:

1. Leaking shock oil: If the shock is leaking oil after the oil change, check that the seals are properly seated and not damaged. A worn or improperly installed seal is usually the culprit.
2. Air pressure not holding: If the air pressure is not holding, inspect the shock valve and seals for damage. If everything appears intact, recheck the air can and ensure it’s correctly sealed to the shock body.
3. Excessive noise or poor damping: If the shock is making unusual noises or the damping feels inconsistent, it may indicate air or dirt trapped inside. You may need to perform an additional cleaning or check for air bubbles in the oil.

Customization and Optimization for Better Performance

Once your oil change is complete, there are a few adjustments you can make to optimize the Bomber CR Coil’s performance:

1. Adjust rebound and compression settings: After reassembling the shock and setting the air pressure, fine-tune the rebound and compression settings. These adjustments allow you to tailor the shock’s performance to your riding style and the terrain you ride on.
2. Consider different oil weights: If you’re seeking a different feel, you can experiment with different oil viscosities. Lighter oil can result in a faster rebound, while heavier oil offers slower rebound and firmer compression.
3. Check the spring rate: The Bomber CR Coil is compatible with different spring rates depending on your weight. If you’re not getting the desired ride feel, consider swapping to a different spring rate that better suits your needs.

Comparison with Similar Models

While the Bomber CR Coil stands out for its rugged [paid link] coil design and easy maintenance, it’s important to compare it with other shock models in the market:

• Fox DHX2: The Fox DHX2 is another coil shock often compared to the Bomber CR Coil. The DHX2 offers more adjustability, especially in terms of high- and low-speed compression adjustments. However, the Bomber CR Coil is simpler to maintain and often more budget-friendly.
• RockShox Super Deluxe Coil: The RockShox Super Deluxe Coil offers a more advanced damper design and a wider range of tuning options. However, the Bomber CR Coil provides a more straightforward approach for riders looking for a durable, no-fuss coil shock.

Understanding Compatibility with Other Drivetrain Components

The Bomber CR Coil is designed to work seamlessly with various drivetrain components. However, there are a few things to consider when pairing it with other systems:

• Rear triangle compatibility: The Bomber CR Coil is compatible with most modern bikes, especially those with a coil shock mount. Always verify that the shock size (eye-to-eye and stroke length) matches your frame specifications before installation.
• Brake and wheel compatibility: Coil shocks tend to be heavier than air shocks, so ensure your bike’s brake system and wheels can handle the additional weight. This is especially important for aggressive riders or those using larger wheels.

By following these steps, you’ll ensure that your Bomber CR Coil continues to provide optimal performance for your riding adventures.