HMF Exhausts / Tech Resources / Repacking Tips & Services

Tuesday, February 10th, 2009

Repacking Tips & Services

For complete instructions on how to repack your exhaust, click here.

What's the Packing For?
Packing material's main function is to dampen the exhaust pulse wave. With no packing in the exhaust, dB will increase to extremely loud levels. It's also an insulation barrier to protect the muffler shell from hot exhaust gasses and keeps performance at it's peak.

Maintenance
Muffler packing is a wear item and should be inspected at least every 15-30 hours of operation. If you run the exhaust under water/mud, it will render the packing material useless. The packing material was designed for racing or normal use and was not intended to be run under water/mud. Cleaning the muffler core perf tube holes with a wire brush is extremely important. Mud and exhaust build up can clog the holes in the perf tube. Also, cleaning the spark arrestor screen with a brass bristle brush will do the best job at cleaning the fine screen without destroying it. Never use a wire brush to clean the spark arrestor, it will damage the fine screen and render the spark arrestor useless. Servicing your packing material on a regular basis you will get the most performance out of your HMF system for many years.

Manufacturer's Warranty
Muffler packing is not a warranty item and it will break down over time. Therefor it's not covered under the HMF 2 year limited manufacturer muffler warranty. Your HMF muffler is considered a "working" part and should be inspected/serviced on a regular basis just like any other mechanical part of the machine. Failure to maintain muffler packing material will cause damage to the muffler shell which is not warrantable. Use of aluminum or steel rivets will not work when you repack your exhaust yourself and will void your HMF warranty.

Repacking Service
We strongly recommend using our repacking services to repack your pipe. You can see a list of service here.

Repacking the Exhaust Yourself
You will need an air riveter to disassemble and reassemble the rivets.
To keep your HMF warranty you must use the stainless steel rivets we offer when re-assembling. Failure to use the stainless steel rivets we offer will void your HMF warranty.
Work safe, this procedure requires you to put your hands in tight places, make sure the engine, exhaust system and surrounding areas are cold before starting the removal process.
Make sure you secure the machine in such a way that it cannot be moved or started until you have completed your work.
Before start up, make sure that the exhaust system/slip on (headpipe (s), s-bend (s), muffler (s) are clear of any plastic, electrical, fuel, control cables, hydraulic lines or anything else that high heat of the exhaust system can damage.
*ALWAYS refer to your FACTORY SERVICE MANUAL for specifications, procedures, or for any other information not provided here.

Common Questions:

Q) How do I know I need to re pack the muffler?
A) If you introduce water or mud into the muffler/packing you will need to re pack more often.
A) If you do not recalibrate the air fuel ratio the internal exhaust temperatures will rise and the packing will burn out.
A) You notice that performance and or sound levels are getting worse.
A) You tap along the muffler body and it sounds hollow instead of solid.

Q) Can I put just any packing in there?
A) We suggest that you don't. We use a special high temperature material sewn into a pillow. This design reduces the “blow out” that you will get with normal fiberglass packing. Remove the muffler from the machine.