It’s no secret that FMF is one of the industry leaders when it comes to 4-stroke exhaust systems for dirt bikes. With an FMF muffler, you get great sound and excellent power output as well. In this tutorial, we show you how to install a full FMF exhaust system on a Honda motorcycle.

Jay Clark with an FMF Exhaust and a Honda CRF450R

FMF Exhaust System Installation Instructions

Jay Clark shows the process in an installation video shot at his shop in Sun City, California. He demonstrates on a Honda CRF450R, but there will be similarities with any other dirt bike. The video is embedded here, but written instructions are also provided underneath for your convenience.

What You Need to Begin

FMF Factory 4.1 RCT Silencer with Carbon End Caps

Of course, the first thing you need to install an FMF exhaust on your dirt bike is… an FMF exhaust! Assuming you’ve already got that, it’s best to have a few useful tools on hand as well. And it never hurts to have a spare set of hands around to help out during the process.

Several Different Service Manuals Tusk Deep Socket T-Handle Wrench
Service Manual T-Handle Wrench
Tusk 6 in 1 Screwdriver Tusk Exhaust Spring Tool
Screwdriver Spring Hook

Of course, your service manual is perhaps the most important thing you’ll need. It will detail what hardware you have on your machine so you know exactly what tools you need. It will also explain the process of removal and reinstallation of your exhaust system. This is important. While there will be similarities with the process on a 2013 CRF450R, there will also be differences, and that is where your motorcycle’s specific service manual will be invaluable.

Remove the Old Exhaust System

  1. Remove the surrounding components.
    1. Remove the seat.
    2. Unscrewing a Bolt to Remove the Seat
    3. Remove the side panel (both panels on a dual exhaust CRF450R).
    4. Removing a Number Side Panel
    5. Loosen the mid-pipe clamp.
    6. Loosen the Mid-pipe Clamp
    7. Loosen the clamps on each of the mufflers (if applicable).
    8. Loosening the Muffler Clamp
    9. Remove the mounting bolt on each muffler.
    10. Removing the Mounting Bolt on the Muffler
    11. You can now slide one of the existing mufflers off. It has a gasket which holds it snugly in place, so you may need to work it a little bit in order to remove it.
    12. Removing the Muffler
    13. Remove the mud flap with a Phillips screwdriver. There are two screws. While this step is optional, it will make the process easier for this particular bike.
    14. Removing the Mud Flap
    15. Remove the plastics surrounding the back end of the frame.
    16. Removing Plastics

  2. Remove the old exhaust system.
    1. Remove the hardware that mounts the mid-pipe to the frame of the bike.
    2. Unscrewing a Mid-pipe Bolt
    3. Remove the entire mid and tail sections of the exhaust system. You’ll need to wiggle it free a little bit in order to take it out.
    4. Removing the Mid and Tail Sections
    5. Remove the two nuts on the header pipe at the front of the cylinder head.
    6. Removing a Nut at the Cylinder Head
    7. The stock flange might be bent. If it is, you’ll need to pry it loose.
    8. Observing a Bent Flange
    9. Remove the head pipe. If the stock gasket is in good shape, you can reuse it; however, it is always best to have a new one. They can be found in our OEM parts diagrams.
    10. Observing a Reusable Stock Gasket

    Install the FMF Exhaust System

  3. Install the new exhaust head pipe.
    1. Put the new head pipe in place. It should match up where the stock components came off, so it shouldn’t be too difficult.
    2. Putting the FMF Head Pipe in Place
    3. This particular FMF pipe has springs on the header – many will not. If it does, put the springs on the flange and then put it in place. It is often easier to start the springs at this stage rather than later.
    4. Putting the Flange with Springs into Place
    5. Install the nuts onto the studs loosely so the pipe can still move around some. If you tighten them all the way down, you might not be able to correctly align your mid-pipe or mufflers. In order to tighten them both evenly, you might want to alternate back and forth between the two.
    6. Tightening the Flange Nuts
    7. Attach the springs to the head pipe. This is most easily done with an exhaust spring hook.
    8. Attaching the Spring to the Head Pipe with a Spring Hook

  4. Install the new mid-pipe.
    1. Put the new mid-pipe into place. On the FMF exhaust system, there is no gasket; it’s just a metal-to-metal fit. You’ll just need to wiggle it into place.
    2. Sliding the Mid-pipe onto the Head Pipe
    3. Align the mid-pipe with the mounting holes. Put the bolt into place. Get it started, but don’t tighten it at this point. You want it loose.
    4. Placing a Bolt into Place on the Mid-pipe

  5. Install the mufflers.
    1. Slide the mufflers onto the mid-pipe.
    2. Sliding a Muffler onto the Mid-pipe
    3. Place the stock bolts into the muffler mounting brackets. (If your particular bike requires new bolts, FMF will supply them. On the 2013 CRF450R, the stock bolts work fine.) Since all of the components are installed, you can completely tighten the bolts.
    4. Tightening the Muffler Bolts

  6. Reinstall the surrounding components.
    1. You can now tighten the mid-pipe bolt.
    2. Tightening the Mid-pipe Bolt
    3. You can also completely tighten the header nuts.
    4. Tightening the Head Nuts
    5. Reinstall the plastics and side panels using the same hardware you took out.
    6. Reinstalling a Number Side Panel
    7. Reinstall the seat. Reuse the same bolts you took out.
    8. Reinstalling the Seat

Let Her Rip

There isn’t anything quite like having a new exhaust system. It looks great and sounds better. And best of all, it will enhance your dirt bike’s power.

Don’t forget that every exhaust system is designed on a machine-by-machine basis. To see what is available for your specific motorcycle, check out the dirt bike exhaust section at Rocky Mountain ATV/MC.

Do you have any additional insights on installing FMF exhaust systems? Take a moment to leave a comment below.

Technician Disclaimer

By Jeff Baker