Workshop: Exhaust Repack

Cassandra

• April 06 2009
• 1,221 views
• 1 comment

We caught up with Mark Tilley of Dubach Racing Development to give you the step-by-step details on how to take care of one of the most overlooked maintenance procedures on your ATV—repacking the exhaust. A freshly repacked exhaust system helps provide proper engine performance and is also a major factor in keeping the exhaust note down at a reasonable and legal decibel level. As you will find out, correctly repacking your exhaust system is a very simple procedure that can be done with just a few select hand tools.

Step One
The first step to repacking your ATV’s exhaust system is to remove the tailpipe section. This usually requires no more than removing one or two mounting bolts and sometimes an exhaust clamp. On certain exhaust systems, such as this DRD unit, you will also have to remove the end cap and end tube.

Step Two
The next step is to remove the exhaust canister from the muffler. Some exhaust systems will be riveted which requires you to subsequently drill out the rivets. Other exhaust systems, such as the one shown here, are merely put together with screws, Allen bolts, or Torx bolts. Before removing any screws, tap them firmly with a metal hammer to help loosen them.

Step Three
With the bolts or rivets removed, determine if the mid pipe and the canister are sealed together with silicone. If they are, cut the bead of silicone with a razor knife. Now holding onto the mid pipe, you can knock the canister off with a rubber mallet or the edge of your workbench against the hanger mount. Thoroughly cutting through the silicone will make disassembly much easier.

Step Four
In a well-ventilated area, slide the packing and perforated core out of the canister. Remove all old packing from the perforated core and the canister for disposal. Be sure to wear gloves as packing is made of fiberglass and is very itchy. If you happen to be working on a two stroke you will need to clean the perforated core thoroughly with a wire brush.

Step Five
There are several types of packing available, the most popular and probably the best is pillow packing. The DRD pillow pack comes pre-wrapped onto a convenient cardboard installation tube. If you are installing standard pillow packing or sheet fiberglass packing you can use masking tape to help keep the packing tightly wrapped around the core.

Step Six
Slide the canister carefully over the packed perforated core using your fingers to keep packing from squeezing outside the can. Use extra caution to be sure that the can is assembled correctly and not upside down. You will need to use your finger in the end of the exhaust to ensure the perforated core is correctly centered in the end of the canister.

Step Seven
Once you have the core correctly lined up make sure that it is engaged in the end plate, and that mid pipe cap is engaged into the canister. Now hit the can against a block of wood in one swift motion driving the core into the end cap. If done properly, your screw holes should now be lined up.

Step Eight
Reinstall the screws or new rivets between the can and end caps. Apply a light continuous bead of clear high temp silicone around the connection of the mid pipe and canister. Wet your finger to wipe off the excess. Reinstall any end tubes or end caps. Now you are ready to install your freshly repacked muffler back onto your quad. Enjoy that newfound horsepower and quieter exhaust!