Time to repack

[Rocketman]

I need to repack the silencer on my 250r. It has a DG silencer and it comes apart easy enough, I'm just wondering what everyone's favorite packing is? I would like to try to make the thing a little quieter if I can.

And why do they call them silencers on 2 cycles and mufflers on 4 strokes? Mine sure isn't very silent....

[Nuthinspecial]

Lets just call 'em spark arrestors. :thumbsup:

[250sx]

try running it without one. :D :eek:

[jenndnn3]

Ok I may be thought up as crazy but I repacked mine with house insulation. This was on advice of dealer/mech at local shop. And yes I took the paper off. Jen

[Rocketman]

jen, really? And how did it work? So what R value do I get?:D

[jenndnn3]

I have the cobra on the 200x. I really never thought it was loud but at the time definatly louder then the hubby''s stock 350x. I Didn't have a spark arrestor for it so I pulled the core to see what I could do and found I had no packing left in it. Took it in and chatted with some reps at local shop about gettin arrestor and could I just replace with reg insulation. I am a cheap/stingy women (I like my shoes) after hearing all cost involved. I had a freind do homemade job on the arresting and repacked put it back. It did muffle it however am not sure what its rated at hasn't been tested. I don't see very much difference in performance at all. But it does seem to have a definate Putt Putt with seperations versus a continueing rumble. I'm not sure I explained that well. Talk about a backwards backyard mechanic huh.:lmao: Hope that helps. Jen

[jenndnn3]

Oh yes I forgot I am under the impression that 4stroke exhaust systems do not make that much of difference based on what you use. That is opinion I could be wrong. However on 2 strokes I would be more wary of just expermenting due to the differences in the way the exhausts are used. I know very little about 2 strokes. Jen

[Fuzzy]

Made sence to me Jenn. I have heard of people doing that before. And when you look at a packing all it looks like is insulation wrapped around the spark arrester. Anything to break up the exhaust tone will muffle it.

[200x_Basket]

does the packing affect the performace or just the noise? i can live witht eh noise but i wont give up any HP. i need to repack all of my rides

[jenndnn3]

I honestly did not notice any power difference. I do nto know if it will affect a 2stroker. Jen

[250sx]

I don't think it will make that much of a difference.

[200x_Basket]

i'll just get some $.99 ear plugs :D

[turbo]

yesterday, while talking to a mechanic that was workin on my quad, yes sunday, hes a good friend of mine, but ne way, he said like jenn did, on a 4 stroke, the only differance the pipe actually makes is sound, and throttle response, on a 2 stroke it does add power also, but a pipe will alow you to change jets and help the engine that way, but he said that the actuall pipe doesnt change any power, just the throttle, its the jets that are making the power when that route is taken.

[Mr. Richard]

HEY TURBO , you got it backwards!!!!! the reason you have to change jets when you change a pipe is because the pipe makes more efficient use of exahust gas. therefore needing more or less fuel .:D :D :D

i too have and still use insulation in all my silencers!!!!!!

tell fmf there pipes don't do anything :D :D :D

[Dirtsquirt]

Wow Kasey, I thought you knew! Thats why i don't run that FMF crap on any of my bikes.


The best packing is "Silent Sport", needs packed less often and also quiets it down that extra DB or so.

When your packing blows out it a silencer you lose backpressure and heat. As some of you probably know ring-dings depend on pressure waves within the pipe to keep the incoming fuel/air mixture in the cylinder, with blown packing this ability degrades and makes the bike preform below it's potential (allowing the unburnt fuel/air to escape into the exhaust).

Now onto heat, heat is needed within the pipe to keep these "waves" at thier maximum potential. hot air expands and increases pressure, with blown packing the pressure is reduced because heat is lost, thus screwing up the entire "efficiet" 2-stroke theory.


Heh, anyways....that is why we paint our pipe with heat paint or coat them.


This technical insight provided by:


-Dirtsquirt

[jenndnn3]

Ok I'm gonna learn somethin here...Dirtsquirt is that only for a 2stroke then?? On a 4 you wouldn't need that back pressure right? Thx for answerin a dumb question....Jen

[Dirtsquirt]

well, sorta, the stuff I typed up earlier was 2-stroke only, 4 strokes need backpressure if you have any hopes of making bottom end power (dragsters have short unrestricted pipes for top end pull)

I don't know if this is making any sense at all....





:p

-Dirtsquirt

[jenndnn3]

It Kinda makes sense. But I thought 4 really didn't need that back pressure?? Also on 2stroke would insulation then be more effeciant because of the fact it helps hold the heat? I know I am gonna start a debate here on what to use....but I am trying to understand how they each work. Fuzzy explained this a bit to me a while back but I am a ditz sometimes. Thx I am sure more question will arise..... Jen

[fishinmagician]

So, how tightly do you pack this stuff in there?

[jenndnn3]

On the insulation.....it's actually not very much....one wrap. Now the weird thing is I never thought my pipe was loud to begin with. Yeah it was louder then the stock bigboy, but not much. I could prob handle puttin another wrap on it but I am not gonna unless I don't p*** the noise test. I don't think it will be a prob, because I swear it is not loud. I heard a really loud pipe on that 350 I look at yesterday and it was very loud....plus they claimed to have just repacked it. The only reason I did this to begin with was because I wanted to fix the spark arrestor and thats how I discovered no packing. Jen

[roadx]

i think Dirt Squirt is just trying to simplify the exhaust process, 2
Strokes and 4 strokes both use waves(scavenging) to help make a vacuum to help pull more gas into the motor. backpresure, waves, scavaging what ever you want to call it helps with low end, and as DS descriped, open pipes are only for top end performance.
on all the new two stroke they have powervalves to help in controlling the length of the pipe and stroke, a valve slides up and down in the exhaust port to make the stroke longer and to adjust the "wave" or scavenging. you can really notice when a powervalve gets stuck, you will either have yop end or bottom end.