Dr. D Carbon Fiber Exhaust Repair

Has anyone attempted to repair a carbon fiber exhaust? I have the Dr. D carbon fiber muffler on a 2009 YZ450 I recently bought and apparently the previous owner did not repack it soon enough and it developed a soft spot on the number plate side of the muffler. It is not worn through or cracked so i was debating either putting some epoxy on a stainless steel plate and bridging the soft area to the stronger area and then riveting it in place or buying a carbon fiber repair kit and laying a couple layers of carbon fiber onto the weak area. Does anyone have any thoughts on this or what would be the best way? I called DrD and they would not just sell me a replacement carbon fiber can (or SS which I would prefer). They would however let me send it back for repairs but I figured I could still take a shot at it because either way the can is toast. Also, what approximately does my muffler exhaust temp get to?

Edited by gabrams
... what approximately does my muffler exhaust temp get to?
That depends a great deal on the condition of the packing, which is why that's so important to a CF can. (BTW, the cans on both my SS DRD systems are aluminum) A well packed muffler can still reach temps of over 300 ℉. It can go much higher with a hole in the packing. The mid pipe at the muffler can run around 500 or higher fairly easily.

The carbon fiber used for the cans uses a high temp resin. Typical resin like that found in a cf repair kit won't hold up to the temperature. You could try using a little JB weld on a thin piece of tin on the inside of the can like you initially mentioned. As long as you keep good packing in it that might be fine.

On a side note, I bought a carbon fiber silencer that already had a soft spot in it just like you describe. I got it cheap and figured I would just run it. I repacked it often and the spot never got any worse and never cracked. After 2 years I am still using it.

Just my mind wandering around on its own, but a double layer of Maier heat tile (bottom of the page) between the packing and the can on the inside might also be effective.

Thank you very much.

Here's a pretty good resin that'd work to fix the soft spot. link

My favorite resin is Resin Services' HTR-212 resin with HT-386-99 hardener. It can handle up to 350-400f, is clystal clear, semi-flexible and super tough. The only down side is the price: $100/gallon, and they don't sell it by the quart. If you plan on reskinning your muffler with another layer of cf, it might make sense to buy a whole gallon, then make a few carbon parts to match the muffler!

Edited by lostonmonday

I had the same problem with a c/f muffler on my 09. I tipped it over in a corner and my boot was under the number plate and it kinda made the cf soft in one part. I just ordered a alum one from Dr.d. But I do wanted to fix this one and use it as a spare. I was just gonna use JB weld on the inside, which I'm sure would work just fine! But haven't gotten around to doing it yet..

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