Hi Hal,
Information central here to help.
Of course there have been a few changes to the muffler insert over the last several years. The early NE5s used a smaller pipe [same as the WC-1] and some had the WC-1 type insert. Around this time I worked with a muffler expert named Tom Hand, and we supplied a really nice insert [either in black or chrome] and used American labor [welding, machining, painting or chrome process], and quickly sold out [except for the one I sent to a company in TX]. Later the NE pipe was enlarged, and a different insert was supplied, and later a much better version apeared in the pipe [very similar to the earlier Tom Hand design without the stinger]. Here are the facts about the inserts, the first inserts were very restrictive, and many drilled holes in them to help the flow, the second edition was almost beyond help, and the last edition was pretty good [but all weren't the same]. The second edition simply had a flat plate on each end with a large open chamber in the middle, which caused massive turbulance. When I re-worked a new motor for someone at the TX company [you know, hopped it up], I couldn't figure why the motor ran so poorly during initial testing, and when I installed one of the Tom Hand inserts, it became instantly clear why. It is easy to tell which is which, and easy to modify the later edition to work better. The best of the bunch [not including the rare Tom Hand edition] is the latest version, and is easy to detect. If the center pipe is attached to the large [approx. 1"] hole at each end, it is a "keeper". However it is very important that the forward end [towards the front of the bike] have a completely level area to allow the exhaust to flow & pulse correctly. Every once in a while I will get one that is welded flush and doesn't require my "touch", but the majority need the tube cut off flush to avoid trapping the exhaust between the center pipe and the outer edge of the insert. And of course the modified area requires a little heat paint to avoid rusting. If you find your bike has the insert with the smaller hole [approx. 7/8"] and no center tube to guide the exhaust flow, just hang it on the wall, make a lamp out of it, deposit it in file 13, or whatever and replace it with the better version. The earlier small WC-1 version can be helped by drilling a lot of 1/4" holes everywhere, but it isn't worth all the labor for the small increase in exhaust flow. Most dealers can supply the better version for approx. $20.00 plus shipping, and of course I have lots of them somewhere in my parts room, including a few of the chrome Tom Hand versions]. Oh, just a few final comments, the sound is great. It produces a really deep tone, and usually enhances the performance in the middle of the power band, and the worst loss was at WOT on Kenny Thomas's "Roller Road" at 1 MPH less [slowed from 68 MPH to 67 MPH].
Have fun,
