New silencer

[AndrewM]

I'm in the process of installing a new silencer from Armours on my 1946 AJS Model 16. When I took the old silencer off, I found that the exhaust pipe pushed into the silencer 5 3/4". When I did a trial fitting of the new silencer, it seems that it has a baffle about 5" from the front of the silencer, which means that the new silencer doesn't go on far enough.

I'm happy to cut some of the excess exhaust pipe off, but am wondering why pipe goes so far into the silencer and whether I am better off cutting the exhaust pipe down by the minimum (about 1") or the maximum(about 4"). Is one going to give better performance and/or better acoustics, or will there be no difference?

If I only cut a small amount off the pipe it will basically butt up against the baffle, meaning exhaust gases will go straight through the single hole in the baffle and the front 5” of the silencer will be doing nothing

[clive]

The original exhaust pipes had a flat plate at the end and holes down the side of the pipe within the area covered by the silencer. If you cut an inch off your pipe plated the end and drilled the holes you would be sure to use all the expansion available in the silencer. You need to cut the same area at the sides as the pipe originally has to allow unstrangled flow. I think pi rsquared is the area of a circle (no mathmatics symbols on my phone) seems a lot of bother i woud just remove an inch of pipe and see how it sounds/performs.