503 Muffler - Is yours plugged?

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503 Muffler - Is yours plugged?

Postby Schoobytwo (Bruce) » Sat Sep 25, 2010 9:14 pm

Checked out a muffler from a 503 today. It looked in great shape on the outside, but I did not have a good feeling about what was going on inside. It seems really heavy and also seemed hard to blow compressed air through. I shook it and as many mufflers do when sitting around for many years, all kinds of stuff fell out of it. After shaking for what seemed like a half an hour and getting most of what I thought was in there out, I still was suspicious.

So I grabbed one off the shelf that had a some rust fatigue on it and decided it would be my sacrificial lamb. I picked a spot on the muffler and cut it in half to see the internal construction. After that and knowing where to cut, I sliced my good 503 muffler into several pieces.

Yikes :o Besides a nest inside, look what I found.....
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There are four baffles in the 503 muffler and the above is shown after I scraped on it a bit. Most of the holes in this baffle were completely plugged. It was so plugged, I had to slice the muffler again to get at the other baffles.
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After some work with the scraper, screw driver and compressed air, the holes are now all open. I guess you would call this carboned up for sure. This muffler would have sacrificed motor performance as the engine would have so much back pressure from the muffler, it might not have even run.

Makes one wonder how many of our mufflers on our sleds are plugging up. This was a valuable lesson for me and more of my mufflers will come apart in the future to insure they are clean.
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If you are going to cut open your muffler, make the slice about 1/2" inside the mounting bracket. This will get you in the middle of the four baffles. Then you can clean all four baffles. I had to make an additional cut to get the nest out and it made cleaning the inner most baffle easier. Then I welded the piece all back together.
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Should work like new :D
Too many Diablos and parts to count.
Yamaha Apex (it outruns the Diablo for sure)
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Schoobytwo (Bruce)
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