Fat Boy 4 Complete Exhaust System - Polaris Predator 500

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INSTALLATION INSTRUCTIONS - DUNCAN RACING INTERNATIONAL, INC.


FAT BOY 4 COMPLETE EXHAUST SYSTEM

MODEL: 2003 - 05 Polaris Predator 500


1. Remove stock exhaust system; it is also necessary to remove the seat and right side panel. Retain (4) stock header nuts, (4) stock header lock washers, (1) muffler mount nut and (1) muffler mount washer from the front muffler mount. New muffler bolts are included with Fat Boy 4. It is NOT necessary to retain the stock muffler bolts.

2. Before starting your Fat Boy 4 installation. You must make sure that the cylinder head exhaust gaskets are intact and in good condition. You MUST make sure the header gaskets stay in place, they are prone to falling out on the Predator. Under normal conditions it is OK to reuse them. If they are missing or in need of replacement they may be purchased from your Polaris Dealer Part # 3087957. DO NOT RUN MACHINE WITHOUT EXHAUST GASKETS. It also a good idea to make sure that the (4) exhaust studs mounted in cylinder head are in good shape. If there is any doubt of there condition. Replace with Polaris OEM studs Part # 3085326.

3. Install the left (#1) header first. Left header has weld seam on the first bend. Install stock header nuts and lock washers, finger tighten (Figure 1).

4. Install the right (#2) header. Right header has a smooth (seamless) first bend. Install header nuts and lock washers, finger tighten (Figure 1).

5. Install muffler and tail pipe assembly. Before installing, apply a fine coat of Hi-Temp silicone in the (2) small tubes on the front side of the tail pipe (Figure 1). Install supplied longer bolt (5/16”x 18 x 1¾”) into front mount first (Figure 1). Then install supplied shorter bolt (5/16” x 18 x ¾”) into rear mount (Figure 1). Install stock nut and lock washer to front bolt. After both bolts are installed, tighten both evenly.

6. Before tightening headers, slide a piece of ¼” cardboard in between headers so they will have a small space after install is complete. Cardboard should be placed beneath the DR tag on the upper header pipe.

7. Tighten header bolts. After header bolts have been tightened remove cardboard.

8. Check exhaust system front to back. Make sure header bolts are tightened correctly and muffler bolts are secure.

9. Oil vent line must be secured. Secure oil line with included bracket. Bracket should be installed on around vent hose on LH side of machine in center case hole above right of C/S sprocket (see Photo on DRI website). *Securing of this vent hose is advisable to prevent hose from contacting exhaust pipes during operation.

10. JETTING MUST BE CHANGED. Before reinstalling side panel it is recommended to change carburetor jetting. Following are some jetting recommendations.

11. Additional Performance and Jetting Recommendations;

For the best performance using your NEW Fat Boy 4 it is recommended to use a Pro Flow Air Cleaner Kit with either a K&N or Uni air filter. The K&N filter makes the best power. DRI recommendeds to run air box with the lid removed.

Jetting Recommendations:
The following guidelines are for Fat Boy 4 equipped Predators with the following type set-ups:

Sea Level Temperature between 60° and 90°

Stock Engine Pro Flow Kit with K&N Air Filter with Lid Removed.

Pilots #47.5
Needle Stock #4
Main Jets: #172.5

The above specs should be an excellent starting point for most installations.
Jetting should check after install.

DR offers a included jet kit that has required jets for initial set up.

Be careful not to run machine to lean-engine damage may result. To rich power will be lost.

Jetting Notes:

Colder temperature requires richer settings.
Higher elevations cause engine to be low on compression and generally require leaner settings.
Air box lid on requires leaner settings than with lid off.

For more information contact:

Duncan Racing International, Inc.
10734 Kenney Street Suite A
Santee, CA 92071
USA
(619) 258-6306

Check our Website for additional Predator 500 Performance items.
www.duncanracing.com