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Exhaust Systems Yamaha® YFZ 450R-X

HMF Racing Full System Exhaust Instructions

For Models: YFZ 450R-X (2009-2021)

Removal

!!! WARNING !!! Before working on your machine, make sure it is parked on a level surface with the transmission in gear and the wheels chocked. Do not work on any machine with a hot engine or exhaust.  Allow time for all parts to cool in order to reduce the risk of burns.

Blackout Exhausts: Take care not to get grease or oils on the exhaust.  Cleaning our Blackout exhaust with harsh solvents, abrasives, or pressure washers will remove the coating and is not covered under warranty.

1. Loosen the (2) bolts securing the silencer to the frame.

2. Loosen the Clamp between the head pipe and silencer.

3. Brace the silencer with one hand and remove the mounting bolts.

4. Pull back and twist to remove the Silencer from the head pipe.

5. Remove the (2) nuts holding the head pipe to the cylinder head.  Save these (2) nuts, they will be used during the installation of the HMF exhaust.

6. Inspect the gasket in the cylinder head for excessive wear or damage.  Replace if necessary (this gasket is not included with the HMF exhaust).

Installation

Note: This HMF exhaust system will come with the appropriate mounting bracket pre-installed to the HMF silencer.  The mounting bracket has been designed with some amount of adjustment, be sure once installation is complete to tighten the hardware securing the bracket to the silencer. 

1. Install the HMF head pipe and loosely install the previously removed (2) nuts that secure the head pipe to the cylinder head.  Do not tighten the nuts, allow for movement in the head pipe.(See Figure #1)

Full System Exhaust Instructions - Figure 1

2. Slide the provided Clamp over the inlet of the HMF silencer.  

3. Carefully line up the silencer's inlet with the head pipe and use a twisting motion to slide the two parts together.  

4. Using the provided (2) M8-1.25x30 Hex Bolts, (2) 3/8" Washers, and (2) 1/4" Spacers loosely secure the silencer to the vehicle's subframe.  

Note: The 1/4" Spacers go between the HMF mounting bracket and vehicle's subframe as pictured below.(See Figure #2)

Full System Exhaust Instructions - Figure 2

5. Check for clearance between the exhaust and all moving parts, adjust as needed.

6. Tighten the (2) nuts securing the head pipe to the cylinder head.

7. Tighten the (2) silencer mounting bolts to the subframe as well as the (2) bolts securing the silencer to the mounting bracket.  

8. Tighten the clamp between the head pipe and silencer inlet.(See Figure #3)

Full System Exhaust Instructions - Figure 3

9. Remove the (3) screws from the original headpipe's heat shield and transfer the heat shield using the original hardware.  A small amount of medium strength loctite is recommended for these screws to keep them from coming loose while riding.  (See Figure #4)

Full System Exhaust Instructions - Figure 4

Wipe off any fingerprints or markings using a soft cloth and mild detergent such as soap and water or glass cleaner without ammonia.  Once the exhaust heat cycles any oils left on the exhaust may permanently imprint.

If you received a stainless steel exhaust without the Blackout coating it is normal for the pipes to change color as they heat cycle.  

The HMF Blackout exhaust will smoke and put out an odor for the first full heat cycle as the coating goes through its final curing process.  It is recommended to allow this process to happen in a well ventilated area.

All systems will produce a smoke out the end cap after a short initial heat cycle, this is the packing material bedding in and is completely normal.

Check all hardware after a few hours of riding to ensure nothing has come loose.  

Discussion

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