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USED YZ426F

Muffler Packing

34 posts in this topic

I want to repack the stock muffler on my '00 YZ 426, but the bike shop only has packing material for 2S mufflers in stock.

Is there a difference between 2S and 4S muffler packing?:thumbsup: Any suggestions on what kind of packing I should get?

Thanks in advance for the advice.

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4T packing can stand more heat, for one thing. Find a shop that sells the FMF 4-stroke packing. It reasonably priced, and works well.

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4T packing can stand more heat, for one thing. Find a shop that sells the FMF 4-stroke packing. It reasonably priced, and works well.

Thanks Grayracer:thumbsup:

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sorry for the ignorant question but, aside from noise changes will repacking the muffler give any performance benefit.

I don't care about the noise, over here the louder the better..

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Actually, a freshly packed muffler will perform better than one without packing, or with a big gap in the packing. With good packing, the muffler behaves more like a straight pipe. If the packing is too loose or partially missing, exhaust gas will bounce around in the outer chamber of the muffler, and possibly cause some interference with the way the gas is supposed to travel.

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If the packing is too loose or partially missing, exhaust gas will bounce around in the outer chamber of the muffler, and possibly cause some interference with the way the gas is supposed to travel.

So, should I pack it really tight? Or just enough packing material to fill the void?

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Moose sells a kit for repacking mufflers. It comes on a roll of paper, like toilet paper, that you slide on the core and then you just pull the paper out. It's pillow type packing and makes it really easy. Drill out the rivets where the can meets the pipe, pull the can off, discard the old packing, slide new packing on the core,remove cardboar, put can back over the packing/core and re-rivet the can. Oh yeah, use high temp silicone at the sealing area where the can rivets to the exhaust. And yes it will improve performance as grayracer stated.

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So, should I pack it really tight? Or just enough packing material to fill the void?
If you choose loose sheet packing like the FMF kit, you should be able to use the entire package in the stock can. Wrap it "fairly tight".

Packing mufflers isn't fun. Wear long sleeves and gloves.

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Find a shop that sells the FMF 4-stroke packing. It reasonably priced, and works well.

FMF makes 2 different 4-stroke packings. The red loose stuff is a pain to deal with. They make a roll of white stuff similiar to 2-stroke packing except its real heavy duty, and its more like what the factory uses.

Don't use 2-stroke packing, it won't last more than a few hours.

When I pack a muffler, I wrap it real tight and use wire to secure the packing to the core.

I hate rivets too, instead of using the rivets, I use license plate screws that can be purchased at any auto parts store. The license plate screws have a huge taper and tighten right up and they won't rattle out. And you can't really see them because you don't have to remove the end cap to repack the stock silencer.

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FMF makes ... a roll of white stuff similiar to 2-stroke packing except its real heavy duty, and its more like what the factory uses.
That's the stuff I was talking about.

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That's the stuff I was talking about.

I thought you meant the good stuff, I just wanted to save the guy some aggravation if he bought the red stuff. :thumbsup:

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I just wanted to save the guy some aggravation if he bought the red stuff. :thumbsup:
I've never seen anyone carry that. I'd guess it's unpopular. Sounds like more fun than I'm ready to have.

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We've always used stainless steel wool packing for our mufflers, it last longer by not getting blown out or deteriorating from the exhaust /moisture etc.... some will say that it weighs more but with the small amount you're talking about it really doesn't matter to me, we're talking ounces in difference here. I just repacked one of the bikes about a week ago and it had been a year since I last repacked it, I should have left it alone it didn't even need it yet.

Just some thoughts...

J

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Thanks for all the advice. I will look for the white stuff that comes as a roll from FMF.

My local Yamaha dealer is completely useless unless you want to buy a new bike. Once you do, they become completely useless. They carry nothing to maintain the bikes, only tons of rider accessories.

There is a Cycle Gear store not too far off my normal route home and I am going to see if they have anything in stock. Else I have to go clear across town to the Honda dealer, but will call before .

Took the muffler off the 426 last night and am planning on drilling the rivets out tonight. Need to either root through the nut/bolt drawer or get some SS rivets when I put it back together.

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I'm a fan of the moose packing. It's cheap and very easy to use. It makes repacking a silencer a 5 minute job with no mess or struggle.

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It looks like $21 list for the kit, maybe $16 online. I'd almost pay that for the convenience but they don't list one for DRD pipes, and DRD wants $30 for theirs. $7 for the FMF sheet is a big difference.

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