Replacement exhaust silencer AMC 500 single engine

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Dibnah
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Replacement exhaust silencer AMC 500 single engine

Post by Dibnah »

Greetings all,

The exhaust note on my G3_with_a_500_engine has become noticeably louder. I like the traditional Brit single exhaust note, but it now sounds like an open pipe.

I assume that it isn't standard, no obvious leaks to the silencer or header / down pipe. If the silencer is designed to be repackable then I can't see an obvious way to open it up.

Image

Image

Down pipe = 1 3/4" outside diameter

Suggestions for a replacement silencer please, I am tight with my money!
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jackstringer
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Re: Replacement exhaust silencer AMC 500 single engine

Post by jackstringer »

At the end of the front pipe is there a washer still there or has it "fallen" out?

You could experiment with that and see if it brings the note down a bit.
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Dibnah
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Re: Replacement exhaust silencer AMC 500 single engine

Post by Dibnah »

Thanks Jackstringer, no washer inside the exit to the front pipe. If I do weld a washer into the front pipe then I'd like to get the sizing "right first time"; a 10% reduction in cross section probably won't make much difference, therefore I'll probably aim for a 20% reduction in cross section.

The puzzle is: why has it suddenly got noisier?
raffles
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Re: Replacement exhaust silencer AMC 500 single engine

Post by raffles »

You have the wrong silencer what you have is for a twin. There are lots of single silencers around both new and s/h
Tony
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Dibnah
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Re: Replacement exhaust silencer AMC 500 single engine

Post by Dibnah »

Thanks Tony, my silencer certainly looks similar to silencers as fitted to some 650 twins, but are not the front pipes on 650s 1 5/8" outside diameter? The down pipe on my bike is 1 3/4" OD.

In my limited understanding, the original silencer probably looked like this:

Image
raffles
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Re: Replacement exhaust silencer AMC 500 single engine

Post by raffles »

That would be about right
Tony
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Dibnah
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Re: Replacement exhaust silencer AMC 500 single engine

Post by Dibnah »

Thanks Tony.

To update this, I couldn't find a new silencer in the correct AMC style that was within my budget, and as I try and follow the true path of parsimony, I sssspent £6.70 of my own money on one of those new fangled "dB killers", for insertion into the silencer exit.

Subjectively, it sounds quieter at idle, but still "cracks" at higher rpm. The objective test was encountering two horses (plus riders) earlier today, no adverse reaction from the nags, which makes a change.
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