Better check your Muffler!

[hornetgod13]

Recently I had noticed the sound of my exhaust had been getting louder. I recieved the HMF slip-on for Christmas last year so it has been on my quad now for 14 months and I believe I've riden it 30 to 40 hours during that time frame.

I did a little research on HMF's website and found the following link. HMF Muffler Repacking Service and "How to" Instructions (http://hmfengineering.com/forums/showthread.php?t=2008)

I followed the instructions and pulled my muffler apart and was shocked to find nearly half the packing was gone (see the picture below). I'm glad I checked it when I did. I hope others see this and are certain to check theirs, as well. I'm going to order a new hi-temp silencer blanket directly from HMF tomorrow.

If it's been over a year or 30 hours of ride time you should check your quad's muffler packing

[exrider272]

haha..... when i pulled mine off to cut it down... i didnt find any haha....

[AtvMxRider]

HMF will repack it for $25 plus freight. Thats not too bad of a deal.

[hornetgod13]

Originally posted by AtvMxRider
HMF will repack it for $25 plus freight. Thats not too bad of a deal.

The price is now $35.00

You can either pay to ship your muffler there and back and have them do it or they will send you all that's needed to do it yourself for $35.00

I imagine it would cost atleast 20 to 30 bucks to ship it there and back.

[STUNTIN400EX]

THATS KIND OF CRUMMY. SURE SEEMS LIKE ALOT OF PEOPLE ON HERE HAVE HMF PIPES AND IF HMF PACKS THEM YOU WOULD THINK IT WOULD LAST LONGER THAN 30 HRS!:confused:

when you send it back they give you a new HMF plate also. How can you tell when it needs to be repacked? I bought mine used so I cant tell if its any louder than it was before.

[hornetgod13]

HMF's website recommends checking the muffler every 15 to 30 riding hours. You can see in the picture above that in as little as a year and 30 to 40 riding hours what my muffler packing looked like. I'm going to start checking mine in 9 month intervals now.

I have all the tools required to do the job myself so, I called and ordered the repack kit. The kit includes.

1. 1 tweleve inch wide hi-temp packing/silencer pillow
2. 10 sealed stainless steel blind rivets
3. 2 aluminum blind rivets
4. 1 HMF name plate

The kit cost $35.00 before shipping. They give 25% off if you're serving in the military. It cost me $33.00 shipped.

[hemi400ex]

hey hornet whats the contact info to get the parts set to me, and what branch of military SGT ARMY WV ACTIVE

[hornetgod13]

Originally posted by hemi400ex
hey hornet whats the contact info to get the parts set to me, and what branch of military SGT ARMY WV ACTIVE

HMF: (216) 631-6980
Muffler repack kit. 12" muffler

CPO (E-7) USN Active. Aircraft Mech. Lemoore, Ca.

[07trx400ex]

I know the muffler gets louder without packing, but does it work as insulation as well?

For example, if you never repacked could it cause the exhaust to get to hot and potentially damage the silencer?

[416exfreak]

Hmm.

My dads HMF has always been loud.

My Yoshi has been getting a little louder here lately...maybe its time to get it repacked.:confused:

How can I tell though if my HMF needs to be repacked? Like can I just look inside or something or will I need to drill out those rivets?

[TRXRacer1]

Good info as usual Hornet but you might want to put your own package together next time, $35 is a total rip-off. For $35 you could repack it 4 times.

[hornetgod13]

Originally posted by TRXRacer1
Good info as usual Hornet but you might want to put your own package together next time, $35 is a total rip-off. For $35 you could repack it 4 times.

I'm well aware of the inflated cost but, HMF's hi-temp silencer pillows are specially designed to minimize packing loss and are worth a little more than standard muffler packing. I prefer not to go the cheap route on a $260.00 slip-on exhaust.

[hornetgod13]

Originally posted by 07trx400ex
I know the muffler gets louder without packing, but does it work as insulation as well?

For example, if you never repacked could it cause the exhaust to get to hot and potentially damage the silencer?

It dampens the noise exiting the exhaust and acts as insulation. If enough of the silencer is missing the outside wall of the muffler will heat up and melt the paint or even melt through entirely.

[07trx400ex]

Thanks, that makes sense about the packing. I could always look up the mp for the material on the canister and measure the temps as it gradually wears to make sure it is in a safe range.

AND, Congratulations on QOTM, my favorite part about your quad is the i5500 complete front suspension setup; I want to get those SO bad.

[hornetgod13]

Originally posted by 07trx400ex
Thanks, that makes sense about the packing. I could always look up the mp for the material on the canister and measure the temps as it gradually wears to make sure it is in a safe range.

AND, Congratulations on QOTM, my favorite part about your quad is the i5500 complete front suspension setup; I want to get those SO bad.

Checking the muffler wall temperature might help identify if it needs replaced but, the only way I know to be accurate is to pull it apart. They are stainless steel rivets so you'll need an air powered rivet gun to replace them afterwards.

I appreciate the recognition as the QOTM. I'm looking forward to a new Pro Armor bumper.

[1Fun400EX]

That kinda sucks i have always liked the look and sound of the hmf but to hear it only lasts that long makes me like my fmf even
more. I have had my fmf for 2 years and i was going to repack it last year i took it appart and it still looked almost new just a little bit of soot in the packing was all just cleaned it up with an air hose and put it all back together.

[TRXRacer1]

Originally posted by 1Fun400EX
That kinda sucks i have always liked the look and sound of the hmf but to hear it only lasts that long makes me like my fmf even
more. I have had my fmf for 2 years and i was going to repack it last year i took it appart and it still looked almost new just a little bit of soot in the packing was all just cleaned it up with an air hose and put it all back together. I use the FMF packing in my Pro Circuit and it does lasts a lot longer then the HMF. It's a lot cheaper too.

[CarGuy7a]

Good Thread!! i took apart my WB E2 to fix a crack in the weld on the upper mount on the can and noticed my packing looked the same way. I ran it also about a year and a half and never really gave it any thought to repack until i had to fix a weld defect.

so i ordered the repack kit got it all together and took her for a test ride and noticed that it did sound better and ran better as well.

[2muchquad]

Im pretty sure Moose and Fmf have silencer packing thats got longer strands than the traditional packing so it doesnt blow out as easy.Usually right around $15 or so