Effective Guide To Repacking Your Two Stroke Silencer


In this, I am super excited to teach you guys a detailed process of repacking your two-stroke silencer. So not only are we going to be going into detail on how to repack your two-stroke silencer but I’m also going to go into a little bit of why it is a good idea to repack the silencer.

let’s get to work on that two-stroke silencer. So what we have here is the two-stroke silencer off my CR125 build that I’ll be using on the trail, some two-stroke silencer packing and then some Honda bond high temp silicone. Then the tools we’ll need are going to be scissors, masking tape, a rubber mallet and then a set of Allens here and some degreaser.

To start the disassembly we’ll actually be working from the back of the silencers so closer to your engine. If you wanted to try and disassemble from the front you can’t on these turbine cores because they have it riveted in because they don’t want you to tamper with the spark arrestor so I’ll start from the back here and it’s just going to be a 4-millimeter Allen wrench take it off.



Then how you want to remove the core in the packing from the silencer body is just to take a rubber mallet and bang on your two mounting spots here and eventually that sound sort of pop off of there. So now that we have it this far we can go ahead and remove the silencer core from the silencer body here and you could see this packing was absolutely soaked in carbon so it’s definitely a good idea that we went ahead and replaced this on this bike.

If you guys don’t have a parts washer you can go ahead and clean this up with degreaser it’ll do the same thing but I’m going to go ahead and throw this in the part washer since it’ll make my life a little bit easier. I don’t repack my silencers very often I probably do it every season or so or if I get a new bike that hasn’t been taken care of very well.

But it definitely for a trail bike you’ll want to do it ‘cause the bike will get super loud and you want to do it on your MX bikes too because it does improve performance when there’s a fresh packing in there. Now if we look into the turbine core to silencer it’s hard for you guys to see this but down in here we actually have the spark arrestor.



So on a normal silencer, we wouldn’t have a spark arrestor down there for a race bike but since I’m going to be using this bike on the trails sometimes I want to have a silencer with a spark arrestor in it because that is state law. Normally I’d like to service that but because FMF has made it so they can can’t tamper with it because they have it riveted in there I’ll go ahead and hold off on servicing that I’ll just clean out this area in here.

I’m going to clean this is just with degreaser and then I’ll work a towel down in there to get out all the carbon. And also you’ll want to make sure that when you’re cleaning it to remove the old silicone sealant that kind of lines around here so this should come up pretty easy with some degreaser but you might need to use a gasket scraper on it.

Now that we got that all clean I’ll go ahead and measure my core to figure out how much packing I need to cut so it looks about eight and three-quarter inches. FMF has a packing they sell on their website but I’m just using a generic one from the local dealership that they sold me, it really doesn’t matter when it comes to two-stroke packing where you get it from as long as it’s meant for a two-stroke and not a four-stroke.



Now just take the measuring tape and measure out eight and three-quarter inches on three different spots on our two-stroke packing here. You will want to wear gloves when you do this because this is made out of fiberglass and you don’t want that getting all over your hands and cutting yourself potentially and then I’ll just cut this with scissors and it’ll cut really easy.

Then as we go to roll this up I’ll just kind of roll it up thinks like when you’re rolling up a sleeping bag you just kind of want to roll it over itself it doesn’t need to be super tight but you want it tight enough to where it’ll compress into your silencer. Then we’ll go ahead and slide it down into your end piece here all the way if you needed some masking tape to get it in there all the way this is a place where that would help.

In this case, I didn’t really need any masking tape and then I’ll go ahead and begin to slide it into the silencer, there is a hole in there down by the spark arrestor that you do need to line it up with. And then I’ll take some Honda bond high temp silicone and work it all the way around the pipe that meets up with the silencer.

After it’s all the way around I’ll spread it out just to make sure there are no air leaks in it or anywhere where anything could leak out of this after I put it together. And after you have your silicone spread out all the way you can go ahead and press this piece in there. It can be pretty stiff so you may have to put it upright to get some more leverage and if that isn’t working for you, you can always take your rubber mallet again and just tap it in there the rest of the way.

Then after we get it in there all the way and our bolt holes are lined up we’ll take some medium strength Loctite and put it on our fasteners here and then we’ll go ahead and install them. There’s no need to do this super tight or anything just get it in there snug, if you went too tight you could warp the silencer body.



And after they’re all installed I’ll take some degreaser and make sure to clean off all the silicone remaining around the end of the silencer here. And after you finished wiping your silencer clean that’s it. This is the quick and easy process of repacking a two-stroke silencer.

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