Upgrading your motorcycle’s exhaust system is one of the most rewarding modifications you can make. Whether you choose a premium aftermarket system from Wunderlich or a genuine OEM upgrade, the process rewards patience, the right tools, and a methodical approach. This expanded guide walks you through every step, from selecting the right system to final torque checks, ensuring a clean, leak-free installation that enhances both performance and sound.

Why Upgrade Your Exhaust System?

Before diving into the installation, it pays to understand the benefits of an upgraded exhaust. Stock exhausts are designed to meet broad noise regulations and cost constraints, often resulting in heavier components and restrictive flow. Replacing them can yield:

  • Weight reduction – Aftermarket systems like Wunderlich’s stainless steel or titanium options can shed several pounds, improving handling and reducing unsprung mass on certain models.
  • Increased power and torque – A less restrictive exhaust allows the engine to breathe more freely, especially in the mid-to-high RPM range. Gains of 2–5 hp are common, though a proper ECU remap or fuel controller is often recommended for optimal results.
  • Improved sound – A deeper, more pronounced exhaust note not only enhances the riding experience but can also improve your presence on the road for safety.
  • Aesthetic upgrade – Wunderlich offers sleek carbon-fiber or brushed aluminum tips that complement modern and classic motorcycles alike.

Wunderlich vs. OEM: Choosing the Right Exhaust

Your choice between a Wunderlich aftermarket system and a genuine OEM upgrade depends on your priorities:

Wunderlich Aftermarket Systems

  • Designed specifically for BMW motorcycles (R nineT, R1200GS, S1000RR, etc.) with precise fitment and high-grade materials.
  • Often lighter than OEM parts, with performance-tuned internals.
  • Available as slip-ons or full systems, with options for dB killers to control noise.
  • May require a remap or O2 sensor spacer to avoid check engine lights.

OEM Exhaust Systems

  • Guaranteed to match your bike’s factory specifications and emissions compliance.
  • Simpler installation – bolt-on without ECU modifications.
  • Typically heavier and more restrictive, but reliable and warrantied by the manufacturer.

If you’re looking for a straightforward swap with no tuning needs, an OEM system is safest. For weight savings and a sportier note, Wunderlich is a strong choice. Many riders combine a Wunderlich slip-on with a stock header for a balanced upgrade.

Tools and Materials Checklist

Having everything on hand before you start prevents frustrating trips to the toolbox mid-job. Here’s a comprehensive list:

  • Socket wrench set – 8mm, 10mm, 12mm, 13mm, 14mm, 15mm, and 17mm sockets (common sizes for exhaust flange nuts and hanger bolts)
  • Torque wrench – essential for tightening bolts to manufacturer specs (range 10–50 Nm typically)
  • Hex key set (Allen wrenches) – many OEM and aftermarket exhausts use hex bolts
  • Flathead and Phillips screwdrivers
  • Jack or paddock stand (for motorcycle) – center stand preferred; side stand can work with careful weight distribution
  • Penetrating oil (e.g., WD-40 Specialist or Liquid Wrench) – for rusted nuts and bolts
  • Copper anti-seize compound – for exhaust studs and slip joints
  • Exhaust gaskets (crush rings) – often required when swapping headers or mid-pipes; check your kit
  • Exhaust hangers or inlet pipe springs (if your system uses them)
  • Safety goggles and mechanic’s gloves
  • Rags and a pan for dribbled oil or coolant (if disconnecting any lines)
  • Shop manual or torque specs for your specific model – available online or from the manufacturer

Preparation: Safety and Workspace

Working under a motorcycle demands attention to stability. Always start on a level, hard surface. If using a paddock stand, ensure the swingarm spools are securely engaged. For bikes without a center stand, a front and rear paddock stand pair provides the safest lift.

Wear safety goggles to protect against rust flakes and dirt. Gloves prevent burns from hot exhaust components if the engine was recently run – allow the exhaust to cool completely (at least an hour after a ride).

Step 1: Raise the Motorcycle

Place the motorcycle on a rear paddock stand, or use a center stand if equipped. For Wunderlich slip-on installations on models like the R1200GS, the bike’s own center stand is often sufficient. If you’re removing the header (full system), raising the front wheel slightly with a front stand gives better access to the exhaust flange nuts.

Ensure the bike is stable and cannot tip. Gently rock it to test stability before you begin wrenching.

Step 2: Remove the Old Exhaust System

Work methodically to avoid damaging hangers or gaskets.

2a. Apply Penetrating Oil

Spray penetrating oil on all exhaust flange nuts, spring hooks, and hanger bolts. Allow 10–15 minutes for it to seep into threads. This is especially important if the bike has lived in a wet climate or if the exhaust has not been removed in years.

2b. Detach the Silencer (Slip-On Removal)

For a slip-on replacement (the most common Wunderlich upgrade), locate the clamp or spring connection between the mid-pipe and muffler. Many Wunderlich slip-ons use a spring-pin system; pull the spring hooks with pliers or a spring puller tool. Alternatively, loosen the band clamp with a socket wrench.

Support the muffler’s weight as you release the last clamp – it can drop suddenly. Once free, slide the muffler off the mid-pipe. If it’s stuck, gently twist and pull while applying more penetrating oil. Do not pry with a screwdriver against the pipe surface as it can leave scratches.

2c. Remove the Exhaust Hangers

Most motorcycles have one or two hanger brackets connecting the muffler to the frame or passenger peg mount. Use an Allen key or socket to remove these bolts. Keep them in a labeled bag if they will be reused – Wunderlich often provides new hardware.

2d. Remove the Header (If Doing a Full System)

For a full exhaust swap, you’ll also remove the header pipes. Unbolt each flange nut from the cylinder head using a socket and extension. They are often tight and may require a breaker bar. Remove the header carefully; note the exhaust gaskets (copper or composite rings) at each port. These should be replaced with new ones during installation – check your new system’s instructions.

Oxygen sensors (if present) should be unthreaded with a 22mm wrench. Apply penetrating oil first. Mark each sensor’s location for reinstallation – they are specific to left/right on some models.

Step 3: Inspect and Prepare Mounting Points

With the old exhaust off, clean the studs and mounting brackets with a wire brush. Remove any rust or carbon build-up. Check rubber vibration dampers (often found on hangers) for cracks – replace if worn.

Apply a thin film of copper anti-seize to the exhaust flange studs and slip joints. This will make future removal easier and prevent corrosion seizure.

If your new system includes fresh gaskets (crush rings), fit them onto the head studs or into the header ports as directed. Do not reuse old gaskets – they deform and will leak.

Step 4: Install the New Exhaust System

Now you’re ready to mount your Wunderlich or OEM upgrade. Follow the order below to avoid cross-threading or misalignment.

4a. Position the Header (Full System Only)

Slide the new header into place over the head studs. Tighten the flange nuts by hand initially. Leave them slightly loose – you will adjust alignment once the mid-pipe and muffler are attached. This ensures the system can settle into its natural position without stress.

4b. Attach the Mid-Pipe (If Applicable)

Connect the mid-pipe to the header using the supplied clamp or springs. Do not fully tighten the clamp yet. If your system uses a slip joint, push the mid-pipe fully onto the header and lightly clamp or spring it.

4c. Mount the Silencer (Muffler)

Slide the muffler onto the mid-pipe outlet. Rotate it to align with the hanger bracket(s). Do not force it – gentle wiggling works best. Once aligned, install the hanger bolts and springs or band clamp. If the hanger holes don’t quite match, loosen the mid-pipe clamp slightly and readjust.

Many Wunderlich systems include an adjustable hanger strap that allows fore/aft movement for perfect fitment. Use that freedom to ensure the muffler tip is parallel to the swingarm and centered under the tail section.

4d. Tighten All Fasteners to Spec

With the system fully assembled and aligned, tighten everything in a logical sequence:

  • Tighten the header flange nuts (if full system) to the torque specified in your shop manual – typically 20–25 Nm for most BMW models. Use a crisscross pattern if multiple cylinders.
  • Tighten the mid-pipe clamp to 8–10 Nm (adjustable band clamp) or as per instructions.
  • Tighten the muffler hanger bolts to 10–15 Nm (check manual).
  • Secure any springs using pliers – ensure both hooks are fully engaged.

Do not over-torque aluminum components – they can crack. Use your torque wrench for every crucial fastener.

4e. Reinstall the Oxygen Sensors

If you removed O2 sensors, apply anti-seize to the threads (do not get it on the sensor tip) and reinstall them. Torque to 40–45 Nm. Ensure the wiring is routed away from hot surfaces and secured with the original clips.

Step 5: Final Checks and Test Ride

The last few steps confirm a successful installation before you hit the road.

5a. Check for Exhaust Leaks

Start the engine and let it idle. Listen for popping or hissing sounds near flange joints and slip connections. You can also use a soapy water spray (dish soap and water in a spray bottle) around each joint – bubbles indicate a leak. Shut off the engine immediately and tighten any loose connections.

Check for leaks at the cylinder head ports, mid-pipe joints, and muffler inlet. If a leak persists, you may need to replace gaskets or adjust alignment.

5b. Inspect Clearances

With the engine running (and the bike stationary), turn the handlebars lock-to-lock if applicable. Ensure the exhaust does not contact the shock spring, swingarm, or rear brake master cylinder. If there’s contact, loosen the hanger and reposition the muffler.

Also check that the exhaust tip does not point directly at the rear tire – it can overheat the tire.

5c. Lower the Motorcycle

Remove the paddock stands carefully. Lower the bike to the ground.

5d. Test Ride and Re-Torque

Take a short test ride (10–15 minutes) at varying speeds, avoiding high RPMs initially. Listen for any new rattles or changes in exhaust note that could indicate a loose part. After the ride, park and allow the exhaust to cool. Then re-torque all fasteners once more – heat cycles can loosen things.

Check the exhaust gasket crush rings after the first ride – if they were new, they’ll now be seated fully. You may need to snug the flange nuts an extra 2–3 Nm.

Maintenance and Care for Your New Exhaust

To keep your Wunderlich or OEM exhaust looking and performing well:

  • Clean the outer surface with a mild detergent and soft cloth after each ride in wet conditions. Avoid harsh abrasives on polished or carbon tips.
  • Check the hanger bolts and clamp bolts periodically – vibration can cause them to loosen over time.
  • If you installed a full system, consider a fueling module to optimize the air-fuel ratio for the freer-flowing exhaust.
  • For long-term storage, apply a thin coat of WD-40 to the pipe surfaces to prevent surface rust.

Common Installation Pitfalls and How to Avoid Them

  • Stripped flange threads – Always start bolts by hand. Use a torque wrench. If a stud comes out, replace it immediately.
  • Exhaust leak at the head – Old gaskets reused are the #1 cause. Always install new crush rings.
  • Muffler hanger misalignment – Don’t force it. Loosen the mid-pipe clamp and rotate the muffler until holes align naturally.
  • O2 sensor error codes – On some models, a less restrictive exhaust leans out the mixture. A Wunderlich O2 spacer can trick the sensor into reading correctly without a full tune.

Additional Resources

For model-specific torque values and installation notes, refer to the official service manual for your motorcycle. For Wunderlich product details and installation videos, visit Wunderlich America. OEM parts and diagrams can be found through BMW Motorrad for BMW bikes, or your vehicle manufacturer’s parts portal.

Finally, for tools and hardware, RevZilla offers a comprehensive selection of exhaust-specific tools and gasket kits.

Conclusion

Installing a new exhaust system – whether a Wunderlich slip-on or a full OEM replacement – is a hands-on job that rewards careful preparation and attention to detail. By following this expanded step-by-step guide, you’ll not only achieve a perfect fit and leak-free seal but also gain the performance and sound you set out to achieve. Take your time, use the right tools, and enjoy the transformation on your next ride.