How often do YOU repack your muffler?

I've never given muffler maintenance a try. I have thought about it, but it never seemed important enough to dig into.

Now I have approximately 35 hours run time on my FMF 4.1 can, not sure how often is often enough vs just going overboard on maintenance.

Sure, I could call FMF, I could check my owner manual for what's recommend, or I could see what the guys and gals at TT have to say!

So what say you behind the keyboard bike mechanics?

Is there a change in resonance that could be heard or felt?

Do the repacking intervals get closer together if ridden WOT more often that putt-putting around or vise versa?

Does running rich or lean affect how long packing lasts?

All I know is that I know nothing lol.

 

I do it at top end time on my 2 strokes. So every 150-200 hrs.

Every Christmas break, or once a year.
Looks pretty bad by then, but can't tell any difference after the change.

Same,at top end time.usually use FMF packing,I tried the fly but seemed loud to me.

About every 200 or so hours/ once a year.

 

Joe

If you're racing or riding sustained high rpm every 8-10 hours is the typical recommendation. If you're a casual weekend trail rider, yearly may be more appropriate.

Heat breaks it (packing) down more quickly in a 4 stroke. That can be caused from a lean condition. In 2 strokes, rich conditions and oil saturation is the enemy.

Don't wait for the bike's sound to change. You have already given up a few horsepower and could damage the can if you get to that point.

My sons 100 gets a repack about every two weeks to once a month, he revs the heck out of it, my bike about twice a year.  As mentioned above, depends a little on the riding you do.  With that said, it's cheap and easy to do, and it won't hurt anything to do it early.

I used to use the yellow fiberglass insulation as packing.  I would try wrapping the cores all different ways, tight to loose until I found what worked the best, but I did know this, it only took maybe 3-4 rides before I'd have to repack as the bikes would run a lot better with fresh packing than when it would get blown out or oily.  

Repacking was easy as I'd leave out the rivets and just used a self tapping bolt(s) to keep the end caps on and the core's slid out easily.  Wrap the core, secure it with some masking tape and re-install, it was all so easy and also cheap as the strip of house insulation was huge and seemingly endless.  I'd take some off in as good a sheet as I could, trim it, wrap it and was done.  

Making sure all the holes/perforations in the core is also a good idea.  Getting all the holes cleared with a screw or a nail or some other heavy duty poking device was the hardest part but if one kept up with it, it would never get that bad again.  There was no soaking the core in any sort of cleaner or solvent that would clear all the holes, they always needed to be poked clean.  

If you keep it in good condition they last a long time!  I have taken mine out before at around 30hrs and they look brand new.  So I would say I would never repack it unless there is a problem.  I don't keep my bikes past about 100 to 120 hrs anyways.

Fmf gets loud pretty quick. Stock mufflers packed from the factory last a very long time.

First thing I do with a new pipe, take that damn packing out. Just adds restriction don't listen to the (dum)masses. Loud pipes save lives!!

Lots of variables... skill, type of riding, 2/4t, jetting/tuning, motor mods, etc.

Keeping you

On 11/9/2017 at 10:30 PM, tyler90 said:

I've never given muffler maintenance a try. I have thought about it, but it never seemed important enough to dig into.

Now I have approximately 35 hours run time on my FMF 4.1 can, not sure how often is often enough vs just going overboard on maintenance. Depends... what terrain you ride, how you ride, maintenance, etc. If you've never done it, it wouldn't hurt to pop the can open and take a look, and going forward you can assess how long you should go until the next repack. When inspecting, take a look at the core as well, it will have a steel wool wrap, and as long as it looks intact, you should be good to go. It will take many many hours for that to breakdown, I have 300 hours on a Q4 with the stock wool wrap. 

Sure, I could call FMF, I could check my owner manual for what's recommend, or I could see what the guys and gals at TT have to say!

So what say you behind the keyboard bike mechanics?

Is there a change in resonance that could be heard or felt? Yes to both. Some people will say they can't feel a difference and some can. It can be seen on a dyno as proof though. When you lose packing, you are losing power. As far as sound, when you lose packing you're can or silencer will get louder incrementally. You can expect a few decibal increase in sound when a decent amount packing is missing.  

Do the repacking intervals get closer together if ridden WOT more often that putt-putting around or vise versa? Yes. If you are hard on the throttle and typically a faster rider, you will lose packing faster. It's all about the heat being generated. A casual trail rider will make packing last longer than a B or A class moto kid, if hours are the same for both. Although dune runs at full throttle can be hard on packing as well. 

Does running rich or lean affect how long packing lasts? Yes. Lean running condition's will increase your exhaust temperature, thus breaking it down faster. In regards to 2-strokes, running rich will also saturate your packing and clog the perf of the core's. 

All I know is that I know nothing lol. PS, I'm not claiming to know everything!

Keep in mind that not all packing is the same either. Some packing materials will last longer than others, by up to 2 to 3 times. Also, note that if you pack by hand, over-packing or packing too tightly will increase your sound level as well. As a rule of thumb, for a 4t, if packing by hand, the density should feel like seat foam. For a 2t, the density should feel like an air filter. 

 

 

On 11/11/2017 at 8:17 AM, Ben500RR-S said:

I used to use the yellow fiberglass insulation as packing.  I would try wrapping the cores all different ways, tight to loose until I found what worked the best, but I did know this, it only took maybe 3-4 rides before I'd have to repack as the bikes would run a lot better with fresh packing than when it would get blown out or oily.  

Repacking was easy as I'd leave out the rivets and just used a self tapping bolt(s) to keep the end caps on and the core's slid out easily.  Wrap the core, secure it with some masking tape and re-install, it was all so easy and also cheap as the strip of house insulation was huge and seemingly endless.  I'd take some off in as good a sheet as I could, trim it, wrap it and was done.  

Making sure all the holes/perforations in the core is also a good idea.  Getting all the holes cleared with a screw or a nail or some other heavy duty poking device was the hardest part but if one kept up with it, it would never get that bad again.  There was no soaking the core in any sort of cleaner or solvent that would clear all the holes, they always needed to be poked clean. 

An easy way to handle a carbon baked core, is to take some map gas and put some heat to it, then take a rubber mallet and lightly tap the core and watch it flake off. Just be careful not to distort the core when tapping on it. 

 

Never!! :rolleyes::thumbsup: Stock pipe FTW!! I do have to drain the muffler fluid once in awhile though 

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