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Exhaust Systems Yamaha® YFZ 450R

HMF Racing Yamaha / YFZ 450R / Slip-On / Ellipitcal

For Models: YFZ 450R (2009-2022)

Removal

!!! WARNING !!! Before working on your machine, make sure it is parked on a level surface with the transmission in park and/or the parking brake engaged.
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. Ensure that the gasket between the head pipe and silencer is removed from the head pipe, it will not be reused.  Clean any gasket material from the end of the head pipe as needed.

Installation

Note: It may be necessary to loosen the head pipe at the cylinder head to allow for some movement/rotation of the headpipe.

1. Install the supplied smaller clamp over the slotted end of the HMF mid pipe.  Slide the mid pipe over the head pipe.  Leave the clamp loose.

2. Install the supplied larger clamp over the HMF silencer’s inlet and loosely mount the silencer to the vehicle’s subframe using the provided (2) M8-1.25x30 Hex Bolts, (2) 3/8” Flat Washers, and (2) 1/4” Spacers. 

Note: The 1/4” Spacers go between the HMF mounting bracket and the vehicle’s subframe. (See Figure #1)

Yamaha / YFZ 450R / Slip-On / Ellipitcal - Figure 1

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

4. Tighten the (2) nuts securing the head pipe to the cylinder head (if loosened). 

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

6. Tighten the clamps between the head pipe, mid pipe, and silencer.(See Figure #2)

Yamaha / YFZ 450R / Slip-On / Ellipitcal - Figure 2

Important: After the first ride or first few hours of use, check and re-tighten all hardware as needed. 

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.
Until the exhaust has been heat cycled a few times small exhaust leaks may be noted at any of the connection points or from the rivets on the silencer.  This is normal and usually goes away after a few hours of run time. 

Discussion

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