Modifying a SBP expansion

After many hundreds of miles my "stinger" on my SBP expansion lost it's end cap...

Bummer but hey it had been riveted and re-riveted but still didn't take the rough roads i run every day to work and back.

So like I do I wandered the local hardware stores and welded a 1/2 inch muffler on to the end where the stinger now removed was.
That lasted about 20 miles before their welds broke and I lost the muffler along the road.

So I had to run for four days as loud as it gets and today was my first day off in 68 straight days of work. So I went to work with 3/4 inch nipple and flexi pipe. Hotwater tank stuff. I assume it's for water?

I start with the benefit of having some weld build up from the first muffler so I start with a thick base.

So, I have taken some pictures and I am limited to three per post so I will make several posts.

Here I start with a standard black pipe 3/4 inch nipple.



I cut this down and bevel for welding. Bevelling allows for a better penetration of the two parts and allows more of the pipe to be welded to the flange.



And here after I have ground the flange which had previous weld build up there is a bit of oil smoke and you can also see better how I bevelled the pipe end.

Having that weld build up actually has been a benefit. True there us a flange once the stinger is off and yes there is a 1/2 inch tube projecting but hey, I cut that off and welded a muffler on which broke off ( manufacture welds failed ) before I got home on the first run.

I will mate these two and weld.





Now I know that I can stand more practice with this Lincoln. As funny as it sounds I ran big wire MIG for 8 years.. The kind of welding we need ear plugs and number 12 shade lenses to run.. But this small wire flux core on this Lincoln is no slouch and i can stand to try out the range of settings and get better at choosing what settings I use.
For this project I made a guess on the setting and have no problem grinding down any cold welds or to even the weld out for another pass.

Now I bought the 24 inch 3/4 flexi pipe found in the hot water section of my local Orchard Hardware store. The muffler is the 3/4 inch large one from Tractor Supply.

This is the pipe just hanging.



I happen to have a length of all-thread here and I decided to get some stock that already had holes in it and I simply rough cut and welded some tabs on the all-thread which I welded to the stock idler I have.



Here is the blue-ed nipple.. So I know the exhaust is hot on the way out. The exit is about 1/2 inch and it jets into that 3/4 inch flexi pipe and travels aft past the rear tire.





I have used 1 inch conduit clamps and (not shown) for tomorrow I simply used tie-wraps to hold the muffler still.
I didn't come up with a final mount for the muffler so i need to wander the hardware sections again for parts on that.

This modification has done two things. One the noise is far aft and I like that but it has some how trumpeted the engine sound and now it sounds beefy and bad azz.
Wow.. I'm all good with that as long as it is aft of me and my ear buds.. I hated to have to turn the volume so far up every day and I figure tomorrows run will allow better sound at lower volume. I like listening to NPR as I ride my 45 minutes to work.

I am open to suggestions on hardware to mount the muffler...

I welcome feed back on this project as well..

I do have more stock that the tabs are made out of so I can add a tab.

LOL unthread? sounds like a job for lock-tite

Dave, I can see how that would work as well.

Well in a few minutes I will make the first run to and from work.

I agree...

Hey I ran so well today that I ran at 35 mph with ease but on the way home I made it about 2 miles before the magneto went out.

Lucky I found a good Christian Farmer that gave me and the bike a 12 mile ride home and it was a simple process of elimination which the Magneto was the third thing to check and the number one thing I suspected.

I have another magneto here as well as a spare CDI.. This was the second Magneto to fail me but on two different engines but at the same high RPM context.


So I will ride again in the morning and I will keep the RPMs down. I am interested in how the exhaust preforms in the warmer air of the ride home.

On the final attachment. I may want to add a strap and create a triangle support and that will tame the up and down motion. The leaves stiffening the side to side motion.

Oh okay... I looked but I have a magnifier light and I can look closer. First look has it looking okay but my eyes ya, know..

BTW the ride home in the warmer air was very enjoyable.

I have not had much control on my idle with the idle screw but tonight a small turn increased rpm in a slight way like one would hope it would

Idle is now a reality and a very adjustable thing!

So it was a really nice ride home.. Maybe a great ride that will fade into the next issue but great nonetheless.

I have to put the final mount on hold for a few days. So far the tie-wraps are holding the muffler on fine so I need to focus on another project.
I may be laid-off soon so I may have all the time I need to get all my projects done.. We shall see.
Tonight a Resume is on the agenda..

I give this mod a thumbs up. I now ride at 28 mph as my high easy with 24 mph being the speed the current set-up seems to be the "sweet spot."

So tonight the experience was on the top of my list of rides. I have had a few of these rides and it just gets better as I learn and improve the MaB.

Okay.. More pictures and posts a few days from now.. I have to focus on the job at hand and the next job I need tonight and tomorrow.

After a few rides now I am happy with the separation of engine sound and exhaust sound.

I find listening to the engine to be satisfying to my need to keep abreast of the mechanical status of things.

The exhaust sound is for those watching me go by. It isn't too bad in terms of this being such a small engine.
I interacted with a Sheriff in his car at a 4 way stop and he was looking at me and the bike but hey I have every required element. I think he was looking for something wrong and I felt the engine~exhaust sound was something he didn't expect.
At that time the engine was warm and power was good so I took off with a smooth acceleration after peddling up to 8 mph. I am sure the exhaust sound had him thinking about me and this bike.