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Exhaust Systems Polaris® RZR® RS1

Print Instructions

HMF Racing Big Core Full Exhaust Instructions

For Models: RZR® RS1 (2018-2022)


!!! 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. Remove the silencer cover.

2. Unplug the oxygen sensor from the vehicle's wiring harness.  Unscrew the sensor from the exhaust and set it aside, it will be reinstalled in the HMF exhaust.

3. Remove the (2) bolts and springs securing the silencer to the headpipe.  Remove the (2) springs on the side and top of the silencer while holding the silencer in place.  Carefully remove the silencer from the machine.

4. Slide the triangular rubber mounts out of the frame of the vehicle.

Optional: For better access, remove the right side rear fender by unlatching the (2) rubber straps and 1/4 turn panel lock.  

5. Remove the (6) bolts from the head pipe holding it to the cylinder head.  Remove the head pipe.  Save the (6) bolts, they will be reused to install the HMF headpipe.

Tip: Accessing the bolts securing the headpipe to the cylinder head can be difficult.  Remove the heatshields covering the headpipe and use a long ball-end allen key/socket where needed.  Additional access can also be found by removing the seat and removing the access panel in the firewall.  

6. Inspect the cylinder head's exhaust port surface.  Clean off any remaining gasket material.  


1. Locate the highlighted hole in the frame as depicted below.  Partially install the provided Self-tapping 5/16"x18x3/4 Flanged Bolt to cut the threads in the hole.  Remove the bolt once the threads are cut in the frame.  (See Figure #1)

Big Core Full Exhaust Instructions - Figure 1

2. Install the included mounting bracket using the self-tapping bolt from the previous step along with the included (1) M8-1.25x25 Hex Bolt, (2) 1/4" Flat Washers, & (1) M8-1.25 Nylock Nut.(See Figure #2)

Big Core Full Exhaust Instructions - Figure 2

3. Loosely install the headpipe using the original (6) bolts and provided RZR 1000 Gasket. (See Figure #3)

Big Core Full Exhaust Instructions - Figure 3

4. Slide the silencer over the headpipe.  Secure using the provided (2) M10-1.5x40 Hex Bolts, (2) M10-1.5 Nylock Nuts, (2) 3/8" Flat Washers, & (4) 3/8" Fender Washers. Place the larger fender washers on either side of the rubber bushings.(See Figure #4)

Big Core Full Exhaust Instructions - Figure 4

5. Evenly tighten all (6) bolts securing the headpipe to the engine.

6. Install the provided (2) Long Neck Springs between the headpipe and silencer.(See Figure #5)

Big Core Full Exhaust Instructions - Figure 5

7. Transfer the oxygen sensor into the threaded port.  Apply a small amount of anti-seize to the threads of the sensor.  Be careful not to get any contaminants on the sensor element/body.  It may be necessary to relocate and move part of the wiring harness so that the oxygen sensor can be plugged back into the vehicle's wiring harness.  (See Figure #6)

Big Core Full Exhaust Instructions - Figure 6

Reintall the fender if removed.

-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 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.


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