Name that Pipe!

Hi friends, it's been awhile!
My Tempter project has foundered recently (apparently having a baby significantly reduces project bike time...) But I'm in luck! I've recently inherited this '79 CB750F from my father-in-law to bum around on.
My question is this: can anyone identify the exhaust on this bike? My FIL is convinced it's aftermarket, and I'may tending to agree, if only because it has no way of preventing the center stand from rubbing on the chain. It's a black, 4-1 system and looks to be one piece with an aluminium muffler on it. It seems kind of buzzy to my ear and not-so-pretty loud.
I'm confused because while looking for specs on the F-model, I found the header image on bikez.com for the 79 is this bike's twin. I can't find a NOS/OEM or aftermarket pipe that looks anything like it. I'd like to know:
1- What it it?
2- is the can replaceable or repackable?
Any help is always appreciated!

It is not OEM. It looks somewhat like a MOTAD from the UK from back in the day. There was a company in Australia that made a pipe that looked much like that too. My CB900 came with it fitted.

If the rear end cap is retained with rivets, drill them out and take a look inside. Some cans come apart at the front and some at the rear to repack. Start with an 1/8" or 3mm drill bit and go up if the rivet is larger. Don't go too large unless you have new pop rivets that will fill the new hole.

Thanks teaser; I'll have a look when I get home from work!

Looks very much like a Motad Neta, should be fully road legal and carbs don't need rejetting.
Silencer shouldn't need repacking.
Should be a part number on it.
Motad are still in business and very helpful.

Were all NETA pipes stamped with that name into the can?

Who is the guy running MOTAD now. I want to say it was that endurance racer that built a beautiful DOHC bike - was it Howard Lees or something like that?

Their pipe had a mechanical baffle and no stuffing as I recall. The Ozzie pipe was glass wool.

http://www.motad.co.uk/the-factory/

Just as likely to be made in Canada though. Other than Lang Hindle, who else made pipes back in the day?

I thought all the older Netas have Neta stamped into the ally of the can, the newer stainless ones don't.

Alan Baker used to run Motad, I don't know if he still does, lovely helpful bloke (so is Pete Gibson btw)

Howard Lees ran the Team Bike endurance team, they started off with a CB900 based bike, then went on to a VF750F followed by an RS860, not sure if they continued into the 750cc era.

The CB900 ran an exhaust made by Motad initially, but went to an RSC one once they started getting help from Honda UK.

Bizarrely I've been fitting a stainless Neta to my Z1000 this evening as the Kerker was far too noisy.

Had a peek last night:
No NETA stamping on the can, or easily read serial number (admittedly, I was doing this under poor lighting conditions). Looks to be baffles, not glass. However, the riveting doesn't resemble that on the pictures found when I Google NETA. I don't know. Perhaps I'll leave it alone for the time being.
Thanks for all the help guys!

The back half of it looks very like 1988 onwards FZ750, but I doubt if it is.

I FOUND IT!!
Turns out, this pipe is made by Wolf Racing of Cambridge, Ontario (about 15 minutes from my honetown). I was able - through a couple weeks of dedicated Internet stalking - to reach out to the man himself, Gary Wolf.
From an email in reply to one I sent him earlier today:
"Jason,
That is one of my Pro Pipes from 1984-87 but the muffler might have been adapted from a different model. I positioned the CB Pro Pipe muffler to follow the line of the aluminum footrest casting, running above the axle line at an angle of some thirty degrees.

In those days most US manufacturers used a very tight radius bend because they subcontracted the bending to commercial houses that usually made furniture. In Canada at that time we had a high import tariff so I could not afford to import American components and subassemblies. Instead I made all my own tooling and I could then make parts of the diameters and shapes that were most beneficial for producing power. Americans who were playing the volume game had to compromise because they did not make the investment in tooling, and just bought off the shelf components.

Backing up a bit, in the Seventies before I had machinery and tooling I was filling tubes with sand and heating them to red so that I could hand bend the tubes. This was slow and inefficient from a production basis but the smoother radius of bend gave better flow. Yoshimura also did this for awhile but then went to tight bends from commercial suppliers. If I had been in the USA I would likely have done the same, but because I was in Canada I made tooling to reproduce the sweeping bends using a mandrel tube bending machine that I bought in 1981. I am surprised that some thirty years later you have one of my pipes..."

It's just so cool to find out I have a rare piece of Canadian motorsport history on my bike!