NOS Mufflers fab.. what to do?

[firstripholdmybeer]

I have some NOS MCM cocktails made to fit 1.5" pipes. BUT, I have 1.75" pipe. Here we go... I was told that people used to trim them down back in the good ol days to be able to slip over the 1.75 pipes. anyone ever heard of this? any known techniques or suggestions here?

in the pic you can see I started to trim down one of them. the one that's not trimmed has a slit that had two small "L" brackets on each side it which was to fit a screw and cinch to the pipe. I was thinking I could do the same if I trim them to slip over my 1.75" pipes. what do yall think?

[47str8leg]

I used one years ago without success but ....I was a young lad without the capabilities of a torch. It is called a muffler expander. Ask at a local muffler shop and see what they think about it. It fits inside the pipe and spreads it open internally. For the exact reason you need.

[farmall]

You could cut them to fit, weld to your pipes and hide the weld joints with band clamps (or whatever, there are no rules for art) of your preference. Solid, strong and easily removed with a zip disc. Not everything needs to bolt together. One-piece headers are common because it's strong and rigid.

[Hawkstone]

Short length of 1.5" o/d pipe swaged to fit inside your 1.75" pipe would be easiest surely ?.

[firstripholdmybeer]

I used one years ago without success but ....I was a young lad without the capabilities of a torch. It is called a muffler expander. Ask at a local muffler shop and see what they think about it. It fits inside the pipe and spreads it open internally. For the exact reason you need.

I hadn't heard of these, I'll take it by a local shop. it could help with flattening the tapered ends so the mufflers sit straight on the headers.

[firstripholdmybeer]

You could cut them to fit, weld to your pipes and hide the weld joints with band clamps (or whatever, there are no rules for art) of your preference. Solid, strong and easily removed with a zip disc. Not everything needs to bolt together. One-piece headers are common because it's strong and rigid.

Welding is my plan B, Id rather see what non permanent options I have so it's a easy swap out if I decide to do it later down the road. hide the welds with clamps is a great idea

[firstripholdmybeer]

Short length of 1.5" o/d pipe swaged to fit inside your 1.75" pipe would be easiest surely ?.

they slip in but theres no great way to secure them in place like that

[confab]

Adapter covered with a heat shield?

[Tattooo]

they slip in but theres no great way to secure them in place like that

You can't weld them??????????

[47str8leg]

It's also known as a tailpipe or exhaust pipe expander. Bring your mating pipe with you.

[Dougtheinternetannoyance123]

I have a selection of pipe expanders, 3 different ones. You can buy them yourself although if you dont do much metal fab probably better off to pay a shop to do it for you.

Realistically need to make some small slices along the inlets as only so much stretching is possible. If you have not used such tools before by all means PRACTICE on some scrap materials first. Mine have a central bolt and you crank it and pushes the segmented pieces outward. I am sure you can find suppliers/vendors online selling them.

The problem with mufflers and pipes is, vintage bikes came with all kinds of sizes and types of pipes, So bigger is NOT better. Typical someone with a Harley or vintage Triumph slaps on some big tube drag pipes and makes a lot more noise but goes slower and less power. Drag pipes are for HIGH RPM racing not street so you give up a lot to make noise.

Exhaust science is complicated and lengthy topic, but I deal with a lot of people building a period custom, race bike or a restoration and say, Early 50s Triumph and many of these had 1.5 inch pipes, instead of 1 & 5/8ths or 1 & 3/4s so hard to find mufflers for them. Many complaints a vendor says "SURE! No problem!" and they arrive and inlets are larger and the vendor threw in some sleeves for spacers which pisses off someone trying to not cobble something together.

This is the opposite problem but still the same issue. IMHO cutting and welding it is not a great idea, depending on the bike exhausts shake like crazy and you will get cracking, the mating surface would be concentrated in a small & highly stressed joint, where the original inlet spreads out the contact into a larger area thus stronger.

So swaging the inlets carefully would be the solution.

Just guessing here, But those mufflers sure do look familiar. There was a bike shop in Portland called Cycle Hub, owned by "The Sandy Bandit" or Cliff Majhor. At one time he bought out over a period of time most of the British bike operations and distributors in the US as each one went tits up. TriCor, JOMO, Duarte, NVT etc etc.. He ALSO bought up several accy manufacturers as well and had shipping containers, rail road cars and secret stashes of stuff. All kinds of treasure.

Its a long story but I wrote about it and took thousands of pictures when he finally sold out and a huge sale. The buyers tried selling in bulk but it took longer than expected and got tired of living in a Portland Oregon Hotel room after 2 years, so a guy in Idaho, Ray Spevak bought up a lot of it, (Several eBay IDs, QueenG is the most well known but has 3 others). Some years back he got a divorce from Gina (Long story) and sold a big chunk of it off in a auction in Lewiston Idaho. I was there, and so was a lot of others including many wheeler-dealers.

There was PALLETS and PALLETS of these mufflers and other exhausts. I got some and they show up a lot on eBay. I didnt get the bigger piles as was outbid,, but still have a few. Some i didnt like as they had a small bend at the inlets to cock them up at a angle. What I wanted them for is because the end piece is removable as well as the baffles, They could be made into racing type megaphones. Too bad you didnt ask before you started cutting. Id have to check mine, but might consider a trade or sale. (I also got a pile of bare steel ones and some other variants.)

Uncle Cliffy would take brand new bikes out of the crate, take off the OEM parts and slap the aftermarket accys onto them and then shelve the OEM parts to resell. Confuses a lot of people thinking they have a zero miles original bike in the crate when it was "Customized by Cliff".
I have thousands of photos, Cycle World ripped me off kinda on the story. All I wanted was a pat on the back and buy me a beer, if generous, maybe lunch. But you can read about it here:

https://www.cycleworld.com/2015/07/30/mining-for-old-the-greatest-cache-of-vintage-motorcycle-parts-in-the-world/

http://www.geekbobber.com/2015/09/cycle-hub-cliff-majhor.html

& related, but a epic tale of burglary, theft, stupidity and dope addicts.

https://www.quora.com/Did-you-ever-end-up-benefiting-in-some-way-from-a-crime-that-you-were-the-victim-of/answer/Paul-Towsley

I have a bunch of his stuff, and at one point joked I should marry one of his daughters and inherit the empire, others said the crafty bastard would know my motives and write me out of the will.

He had some cool stuff though. Engine cases with no numbers, frames with no numbers, makes you wonder about some of these restos now? Also Tracy body work, and all those pipes in the background, some NOS BSA & Triumph but others were MCM, Bates stuff, and other accys people go nuts for. Up in the attic was piles of old helmets still in boxes from the 60s and 70s

[farmall]

A properly secured exhaust doesn't dance and crack welds and millions of welded exhaust systems from tiny to huge are proof. Nearly all two (or more) into one headers are welded at the downpipe-collector joint and many like typical Bassanis and Thunderheaders have the silencer welded making the whole exhaust a single piece. (Poor mounting cracked many Thunderheaders through no fault of the weld joints.) If a common welded exhaust joint has cracking issues someone screwed up.

I like the old dirt bike style spring loaded slip joints for easy maintenance and swapping out damaged parts but those were rarely on plated systems and those systems were plated AFTER fabrication. They leaked sometimes but nothing a bead of RTV during assembly doesn't handle.

.Realistically need to make some small slices along the inlets as only so much stretching is possible.

Truth, and the only way to make stretching easy is heat with a rosebud which is great on unplated steel but trashes chrome.

Practice on scrap and decide. You can't lose that way.

Find a good pipe expander. It's common to break cheap ones. I'd lube the threads since they're heavily loaded.

[MOTher]

If you do decide to weld them, you might want to knock up a quick jig to hold everything in place and straight. In the one in the pic the two short pieces that hold the pipe were cut on the end with a 1⅞" hole saw, and the flat board at the bottom has a big hole to hold the muffler in place. In this particular case I was using a muffler from a set of Bub Bad Dogs, but something similar could be done for your MCMs.

[firstripholdmybeer]

Alright guys, thanks for all of the responses. there were way more options than I expected, but it seems welding was the way to go. So I tacked up the front exhaust and I'm going to take it to my guy who always does a killer job. the Rear exhaust will get a clamp and I'll put one on the front pipe to match it for aesthetic purposes.

[farmall]

If you do decide to weld them, you might want to knock up a quick jig to hold everything in place and straight. In the one in the pic the two short pieces that hold the pipe were cut on the end with a 1⅞" hole saw, and the flat board at the bottom has a big hole to hold the muffler in place. In this particular case I was using a muffler from a set of Bub Bad Dogs, but something similar could be done for your MCMs.

[ATTACH=CONFIG]100098[/ATTACH]

That wooden jig is seriously slick. Light, easy to make for single jobs and cheep. Imma copy that and if you're inclined to post it in the How To section it certainly belongs there.

Thanks for posting!