repacking silencer?

[KelvinKDX]

Quick question here that's been puzzling me:

I keep getting this urge to repack my silencer (FMF PCII S/A) on my KDX - but i don't seem to know why i should do it.  The silencer has been on the bike for two riding seasons.

Are there signs that it is time to repack?  Is there a time interval?  I hear of many MX'ers repacking annually.

I've not noticed any great power losses - sound seems the same as always - but when should i do it???  Never comes to mind.

Input welcome. :)

 

[KnoxKDX]

Well, that's a good question, but since I have only the stock silencer I won't be of much help to you. It seems that over time the silencer packing can't help but accumulate oil and gunk, so I would think once a year wouldn't be unreasonable. As far as power loss and noise, the process of oil accumulation will be so slow that you might not actually notice a change to it...kinda like if you work with someone who gains 30 pounds in a year, you won't notice cause you see the guy everyday, but his mom who only sees him at Christmas will!!!

 

[BRush]

Two seasons! :eek: I repack about every 6 - 8 weeks. I notice the sound level drops. Also, unless jetting is totally perfect, spooge will eventually soak the packing material. Let it go too long and the packing blows out and low end will go away. Other times to repack - after any deep water crossing where you suspect the pipe outlet went under.

 

[KelvinKDX]

BRush - thanks - i'm looking for some guidance.  I guess this post may seem kind of stange to those who repack all of the time.

I will probably repack my silencer to see if i notice any difference in noise and performance.

 

[chowder6]

quick tip! to save about $10, i use 1/2 inch thick pipe insulation to repack my silencer...costs $1.39 per roll at home depot and works great....and a roll can last for atleast 2 repacking jobs....just a thought

 

[kev_rm]

i use normal home insulation, about every 4-6 rides.

 

[dave186]

On a two stroke, the packing wont really blow out like on a four stroke, but it will get clogged up with spooge. thats when you need to repack it. check out this website www.performax-products.com they sponsor DRN so check out there packing.

 

[KelvinKDX]

i do have some of the Performax material that was handed out at DW02.  This is what i intend to use to repack with. :cool:

 

[canyncarvr]

A lot of points of view on this for sure.

FmF says 'Don't pack it too tight or performance will suffer.'

Then from some (I didn't copy it) web techline, 'Pack it as tightly as you can.'

re: Signs to repack

Spooge on your endcap (the connection between the arrestor and the canister) is indicative of 'You already should'a done it'

Take yours apart and check it out. After two seasons you'll likely find a wet soggy (smelly) mess.

Last I checked (last week) performax was about 3X the cost of one-each 'sanctioned' (brand name) packing material.

 

[BRush]

I've tried the special Moose packing and I've tried the cheapo Home Depot insulation. I don't really see the benefit of the Moose stuff. About tight vs. too tight: the only time I had a problem was when it was too loose (really loose). There was a dramatic fall off in bottom end.

 

[dave186]

Performax is actually cheaper than the best selling packing (silent sport) and is easier to use. FMF sells some stuff that is very similar to performax, and its about the same price. I think fly and some others sell some plain old fiberglass insulation in a bag for real cheap, but I would never use it. i can imagine trying to get that stuff out after getting all spooged up in a 2 stroke. if you really want to be that cheap, go ahead and use house insulation, but if you give some good packing a try, you might just notice it sounds better, lasts longer and might even give you a bit more power.

 

[BRush]

I’d have no problem spend extra $$$ for “good” packing if I was getting some benefit from it. Easy enough to do a cost benefit analysis:

1) Does bike run better with “good” (i.e. “expensive”) packing?

2) Does bike runs quieter with expensive packing?

3) Is expensive packing easier to repack?

4) Does expensive packing allow you to extend the repacking interval.?

5) Is expensive packing easier to get?

6) Will my friends be more impressed with the expensive packing?


For my own case:

1) Not that I can tell.

2) No. Cheap Home Depot insulation is no louder than the Moose stuff. Have not tried Performax, but will give it a try sometime as I like experimenting. I seriously doubt that this result will change however.

3) Moose packing was harder to pack (it's stiffer). If someone made one of those pre-packaged canister things that fit my silencer I’d give it a try, but cutting and wrapping packing is more or less the same whatever you use.

4) Not that I can tell. You have to figure that new packing is going to spooge up about at the same rate, no matter what the material. .

5) How close is Home Depot?

6) Oh yeah. That’ll happen... :moon:

 

[canyncarvr]

Wow! I heard on DRN that BRush uses that spendy performax stuff in his S/A!!

I am SO impressed!!! I'm gonna run out and get me some right now! Chuck Steahly (of Steahly Off Road fame) has some hangin' on his wall!!

I am sooooo happy!!


p.s.
Anyone want me to pick'em up a FWW while I'm there? Send money!

 

[380EXCman]

How did I miss this one? Im gonna have to spend more time over here in this forum.

I’d have no problem spend extra $$$ for “good” packing if I was getting some benefit from it. Easy enough to do a cost benefit analysis:

1) Does bike run better with “good” (i.e. “expensive”) packing?

Funny you should ask? I compared my packing against silent sport and an unpacked silencer on a dyno. Consitently my packing out performed the more expensive silent sport in the horspower department. Both of us performed better than an unpacked silencer.

2) Does bike runs quieter with expensive packing?

It could but not likely.

3) Is expensive packing easier to repack?

Depends. Those Race Tools cartridge kits are like $22.00 and easier to put in. But is the extra $12.00 to $20.00 worth it to you?

4) Does expensive packing allow you to extend the repacking interval.?

Yes and no. Honestly on 2-strokes durability is not as big an issue as it is for 4-strokes. But if you do have a 4-stroke the answer is yes. You will not find any insulation at Home Depot that will last more than a few rides in a 4-stroke. So you could save per repack but do it 5 times more often not to mention the added labor. (Not everyone loves to repack silencers like I do)

5) Is expensive packing easier to get?

Not always. But I spend more time at my local bike shop than I do at the Home depot. And with this internet deal its pretty easy to get stuff if you are willing to wait a couple days for shipping.

6) Will my friends be more impressed with the expensive packing?

Probably not, but hey with each bag of my packing you get a dyno chart you can cut out and put in you wallet. ;) and a cool sticker to put on your bike.

Whether you use more expensive silencer specific packing or not is not that big of deal. Its important to repack it as often as it needs it. Especially with excessive noise becoming more and more of an issue.

I could point out 100 reason why I think my stuff is best but I dont think this is the place. Check out my site (sig line at the bottom) or click on the banner I advertise on this site. Check out the FAQ's and decide for yourself.

 

[canyncarvr]

Look for the above post to get nuked......Your sig is 'illegal' ain't it? No? Yes?


Anyway......

Hey! I din't get no steenking sticker with my bag-o FmF packing!!

The rube's!

 

[380EXCman]

canyncarvr- I think its ok. I didnt come in here spaming away or anything. You can do a search on silencer packing and most of the threads I posted on I was as objective as I could be. I admit though I am going to be some what bias......:) First and foremost though I try to educate people the importance repacking a silencer. Whether it is with mine or not. Believe it or not but I still get calls from guys telling me that they took all the "fiberglass stuff out that was plugging up their exhaust" and their bike is much faster now.....

 

[BRush]

Originally posted by 380EXCman
I could point out 100 reason why I think my stuff is best but I dont think this is the place.

Like many things in life, sometimes it is not a matter of what is “best” but merely what’s “good enough” . I’m quite willing to pay a premium price for something if the value I get from it makes the expense worthwhile. No Toil is an excellent example of this. I would truly hate to go back to the old messy solvent method of cleaning filters. For packing a two stroke KDX with an aftermarket SA, I have yet to be convinced that the expensive stuff confers enough of a benefit to justify the expense. A performance edge would be nice, but unless it will find a truly huge number of hidden ponies I’m a lot more concerned with sound levels, longevity, ease of repacking (in that order). The $1.50 a pop Home Depot stuff works pretty well and lasts fairly long. Might be different if I had a four stroke, who knows?. This is not a comment one way or the other on your product. I’ll probably give it a try at some point to see how sound levels are affected.

 

[Timr]

Back to the original topic as to how often and why.

Kelvin,

I repacked my FMF silencer last august, and I've only ridden my bike 4 times since then.  After giving it no attention for the past two years, what you will probably find is that the holes on the silencer tube will be carboned over.  Most of mine were when I rebuilt it in august.  This has an effect on the performance of the silencer.  It changes things like back pressure and such since the more carbon build up you have, the more the silencer tube starts to act like a solid pipe.

Noise definately increases and there's other negative effects.  What can you do?  Well, you burn all the carbon off with a torch, or you can use a drill or a punch to tap out all of the holes, or you can soak in carb cleaner and then brush it with a wire brush.  Be sure it's good and dry if you go the carb cleaner route.

Then repack, with material of your choice, and you'll notice a difference in both sound and performance.

 

[BRush]

The propane torch method works well. Once everything is carbonized, a wire brush clears everything away and opens up the holes.

 

[KelvinKDX]

Alright guys - Thanks for the responses.

I will be repacking it with the Performax material that i have (thanks 380EXCman) from DW02.  :thumb:

i love this site!  :cool:

 

[wallasaki]

Can a factory spark arrester be repacked? Checked the bike, and service manual, am I missing anything? Tried a search - no luck. Shouls I just follow manual for care and upkeep? Thanks in advance.

 

[KDXFreestyle]

I have a 2003 stock KDX 200 S/A mine is unpackable, because it has no packing. lol by the way as most preople know, its welded together, completely.

 

[BRush]

Originally posted by wallasaki
Can a factory spark arrester be repacked? Checked the bike, and service manual, am I missing anything? Tried a search - no luck. Shouls I just follow manual for care and upkeep? Thanks in advance.

No. The stock silencer & spark arrestor has no packing. However, many KDX owners have replaced their stock pipe and silencer with aftermarket units for performance reasons. These do require regular repacking.

 

[wallasaki]

Thanks Brush, figured it was a no go - just wanted to make sure I wasn't missing anything. Very quiet bike, as if it were packed with something.
later

 

[canyncarvr]

A BTW..
A local shop owner (and moto-x'r that ends up in front of everybody most of the time) mentioned he uses 4-str packing material in his kx. He said he's always being asked howcome his bike sounds so good. 'It's been one of my 'secrets',' he said.

I've got a bag for 'next time'.