Melted my FMF PowerCore 2. Why?

I mounted a FMF PowerCore, shoe-horned the "QuietCore" for sounds checks, and things have been fine. I repacked the cannister with MSR wadding, and the directions said to pack the material "loosely", which I did.

Occasionally, whilst riding, a bolt might rattle out where the cannister mates near the mid-pipe, and that will emit a louder exhaust note.

Well, after my 100 mile race this weekend, by the end of it, the bike was noticeably louder, so I figured that I had rattled out one or more of those bolts (when mounted, they are under the right-side number panel, and not all that easy to see) so, last night I started to asses the damage from the race, and it seems like I have melted the pipe!

I took off the seat and side-panel, and all of the bolts that hold the cannister to the pipe/core were still there, but the aluminum all the way around the bolts was gone!

Here is a picture of that. (Bolts were in when I took the pipe off)


Then, when I took the cannister off the core, it appeared that all of the packing material had migrated towards the end of the pipe. Front half was empty, rear end was packed tight. Here is a picture of the packing material in relation to where it was inside...


I know that exhaust was still able to exit via the endcap, but I can see that much exhaust was also exiting out the front of the cannister, and that must have been what melted the cannister.

Did I pack the packing material wrong?

Is this a common problem?

I appreciate any input.


Wow. Thats the wildest thing I have seen in a while.

This teaches me one thing. Dont listen to MSR directions anymore about "packing loosley".

Thanks for the heads up. To bad you had to loose a couple hundred dollars for us to find that out. :):D

Wow i have never seen that before.I would send those pics to fmf and see if they will stand behind their product and replace it.I would think even without packing it shouldn't be melting.

Was that the MSR silent sport packing? :)

Just got done talking with a local pro (Taber Murphy) and he said that he has done the exact same thing to about 4 FMF pipes. Here is what he said:

#1. The packing material might say to pack it loosely, but he said that one needs to get as much in there as you can.

#2. He said that packing material also provides vibration damping, and that my loosely packed material probably migrated a while ago, and that now vacant space up front was now a vibration hot-bed.

#3. Those new vibrations probably caused stress-fractures near the bolt holes, and that allowed the exhaust to vent, which probably blew the pieces out.

Yes, it was MSR SilentSport packing.

So, now I am pipeless. :)

I agree that looks like vibration damage. I have never seen a pipe do that. I wonder if FMF is making that pop can thin. :)

I agree also. Al melts just above 500 deg. C. I don't think you got it that hot. :D Does not take that much vibration to break down Al. though. I always pack as tight as I can, but I don't read directions much either. :)


You can get a stock YZ exhaust really cheap nowdays. They perform almost as well as any aftermarket pipe out there.(allbiet a bit louder mabye) Plus I dont think they look bad.

As a matter of fact, I put on on my bike a couple months ago. Nothing wrong with it. :)

i have nice titanium system that i'll sell you for $250.00

pm me for a picture.

or send me your e-mail

mine is:



I have a YZF can with one small dent. Pay the shipping and you are welcome to it.

I hate to say it, but I think FMF makes a bunch of junk. If you're read any of my posts lamenting about my FMF Megamax II, then you're somewhat familiar with my thoughts on these products. The damage to your muffler isn't very far off from what mine did on many occasions. I had to cut the can and core down and redrill/rivet the thing back together several times. When I finally trashed it, the whole can section was a good 2 inches shorter than when I first got it. I'd say cut your losses and get a non-FMF muffler.

I have the same silencer. It blew at the mid pipe area. Just blew up! It looked like the exit hole from a bigg bullet. It was in a national enduro. I called FMF and they had me send it in. I got a new one in about a week. I have that one still it is almost new if you want it pm me. Then sell the new one FMF gives you :) ---Mike

Not to sound like a smart*ss, but aluminum melts at about 1,200 degrees.


your not a smarta$$ he said 500 C. its close to 1200 F.


Many thanks tctrailrider.

I will use the YZ can until I determine what my long-term solution is to my new-found pipe problems.

Since I just cut a fat check to the Uncle, I gotta lay low on any purchases....

Again, thank you TC Trailrider. :)

Brandon Whallon

Brandon,can you cut down the cannister by say 30mm(mark up the bolt hole centres first)then cut the same of the end of the inner baffle pipe and slip it all back together again!,the pipe will be a tad shorter but it should work just fine,it will save you a few bucks! :)

I think I will do that. The can is not in that bad of shape, the rest of the core and pipe is still in pretty good shape, and still having the ability to be spark arrested and less than 96 dB is important too.

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