The exhaust system on your motorcycle takes one hell of a beating. Rust, dents, scratches, and general weathering will leave it looking like scrap. However, if your exhaust is made of stainless steel, you may be in luck. I’m going to show you some procedures on how to turn back the clock on this critical, yet often neglected, motorcycle component.
The exhaust system I am using for an example is a Yoshimura stainless steel unit for a 2006-2007 Suzuki GSX-R 600/750. I picked it up on Craigslist for $250, which seemed like a great price at the time. The new price of this system would be over $1000, so I figured I would try my hand at cleaning it up and then attempt to resell it for a profit.
The pictures in the ad made it look a lot nicer than it really was. When I arrived to pick it up, I had second thoughts about buying it. I didn’t realize it had a sizable dent in the bottom of the muffler or that the corrosion looked like some terrible skin disease.
“Oh well,” I thought. I could at least try to revive it for the sake of science, or at the very least a Jalopnik story. Here we go!
Tools Of The Trade
The tools and materials shown here represent everything I used to overhaul this exhaust system. Depending on how neglected your exhaust is, you may or may not need everything I’ve listed.
Items like the bench grinder and Dremel tool are not required, but they will save you a few years by speeding up the corrosion-stripping and scratch-removal processes.
Shining It Up
This Yoshimura system looked like hot garbage. I mean, just look at it. I won’t give too many details of the seller whom I bought it from, but let’s just say his residence had wheels and was located in a “park.” No judgement on the man, but this exhaust definitely wasn’t a treasured piece that was kept indoors, out of the elements.
Before I began the monumental rescue operation, I had to first disassemble the system into its individual components. Unlike stock exhausts, which only have three parts (header, mid pipe, and silencer), this Yoshimura unit consisted of eight individual pieces. Each one was thoroughly fused together thanks to a decade of moisture-capturing neglect. I completely drenched every pipe connection with rust penetrant and let it sit for a few hours.
Following a few choice verbs I had the exhaust system separated. What a state it was in!
The initial procedure in the overhaul was to remove the outer layer of corrosion and rust. It’s always a good idea to start with the least invasive method first, such as applying polishing compound. Once you determine that the light approach won’t cut the mustard, progress to the more severe methods such as sand paper.
I knew that polishing compound wouldn’t be severe enough for me, so I went straight to the 220-grit sand paper. I applied WD-40 to the pipe surface and rubbed the sand paper back and forth until the first layer of corrosion was removed. I then progressed to finer sand paper, going to 400 grit then to 600 grit. I used brake parts cleaner to prepare the surface in between each sanding sprint.
I’m not going to lie to you, this is a very demoralizing procedure that makes you want to chuck the whole damn project in the trash. It is dirty, it is time consuming, and it is probably bad for your overall health. But heck, that could be said about just about any mechanical restoration!
Now that the bulk of the rust and corrosion had been removed, it was time to send the pipes to the bench grinder. I fitted a brass wire wheel to the grinder so that the resulting polish would not scratch the metal. The grinding wheel made quick work of the job. The resulting finish turned out pretty good considering what it started out like.
I decided, for the sake of time, that I was satisfied with brushed look of the exhaust system. The shiny, mirrored finish that stainless steel exhaust systems have when new would require many, many more hours of fine sanding and polishing.
Dent Reformation
The center muffler portion of the exhaust has the unique pleasure of being the lowest component on the motorcycle. This means that if you try to hop a curb on your GSX-R while you’re running from the police, the muffler acquires a nice dent.
I couldn’t simply buy a new muffler section from Yoshimura. This meant I had to completely disassemble the muffler to try and remove as much of the dent as I could.
The first step in the disassembly is to drill out all of the rivets that secure both end caps of the muffler.
With all of the rivets removed, you can then separate all of the pieces of the muffler section. Inside of the muffler you will see fiberglass packing material. This stuff is nasty, but you will either want to save it or replace it with new material. I decided to save and reused it.
With the muffler separated, it becomes obvious that the dent was purely a cosmetic defect. The center perforated cylindrical section is where the exhaust gasses pass through which was not affected by the dent.
It was at this point where I observed how difficult it is to reshape metal. It was also at this point where I decided to give up on a perfect repair, and just do something that made the dent, well, less of a dent.
My dent removal “method” was to pass a metal pipe through the center of the muffler skin, and then slowly roll the dent out similarly to how you would roll pizza dough. The only difference was that I was rolling metal, and I was standing on the roller. My body weight was just enough to push out most of the dent. Again, not perfect, but better than before.
Satisfied with the shape of the muffler skin, it was then time to reassemble it. I placed a bead of high-temp sealant around the lip of each muffler end cap, then refitted them to the muffler skin. I re-packed the fiberglass material into the void between the muffler skin and the center perforated pipe. Finally, I riveted it all back together.
The end result for the muffler was much better than before. It was a lot easier to swallow the less-than-perfect outcome knowing that the dent was nothing more than a cosmetic imperfection.
Road Rash Ointment
Dents and corrosion weren’t the only eye sores present on this exhaust system. There were some small scrapes visible on the silencer section. The silencer is the most visible part of the exhaust when installed on the bike. As a result, it is important to get this part as perfect as possible.
Removing scratches from metal can be accomplished in nearly the same fashion as you would do for removing gouges from wood. I broke out the Dremel tool and slowly started to grind back the scratches. The key to this is to apply very light pressure with the Dremel and keep the the tool moving. You don’t want to create an obvious repair area. You want to try and blend with the surrounding metal.
Don’t worry too much about creating a wide grinding area as everything can be polished out. Once you have ground away the depth of the scratch, use your various grits of sand paper to blend the area. You will eventually reach a mirrored finish as you use increasingly finer-grit sand paper.
With one scratch successfully ground away, it was time to tackle the scratch near the carbon end cap. I did not want to accidentally grind away any of the carbon fiber, so I used masking tape to act as a buffer. Using the same grinding progression as before, the scratch was easily removed.
The badge that was riveted to the silencer was looking worn out. Luckily, I was able to purchase a new badge straight from Yoshimura. I also bought some new clamping springs to give the exhaust a fresh look when reassembled.
The badge was easily removed by drilling out the old rivets. Using some degreaser, I was able to clean up adhesive backing residue left from the old badge. I then permanently affixed the new badge to the silencer with four new rivets.
With the scratches removed and the new badge applied, it was time to go over it with polishing compound.
Wiping the polishing compound off with the microfiber towel, it became obvious that the work I had put into reviving the silencer was worth it. It looked almost new!
Laborious Success
All-in, it took about 10 hours to revive this old and neglected exhaust system. I think the results go to show that even if something looks decrepit at first glance, beauty can be unlocked with a little bit of time and effort.
Once the exhaust was cleaned up, I no longer had any use for it. I didn’t own a bike that the exhaust fitted, nor did I have any intention of purchasing such a bike. I immediately tossed it up on Craigslist for $650. The price was a complete shot in the dark because I couldn’t find any exhausts out there to compare it to.
Within two days of posting the ad, a buyer came by and picked it up. It’s a good feeling taking an item like a neglected exhaust system, something that was destined for the trash heap, and turning it back around into an asset that people actually want. While the exhaust rescue did occupy a good portion of a weekend, I just had to reflect on the figures to understand why the restoration made sense:
PURCHASE COST: $250
PARTS & SUPPLIES COST: $100
LABOR HOURS: 10
SALE PRICE: $650
NET PROFIT: $300
You don’t have to be chasing a profit in order to perform such a restoration. If your stainless steel exhaust system is looking a bit worse for wear, you owe it to yourself to bring it back around.
With some elbow grease and a little bit of time, you may just have your crappy exhaust looking great once again.