More on quiet

K

kerf

Guest
After spending the last six weeks in the muffler of the week club, I've resigned my membership. My latest and final creation is a 12 1/2" long, 1 1/4" dia. chrome, straight through glass pack. The removable baffle tube is 5/8" dia. with 74 -3/16" holes and tightly wrapped with fiber glass. Every muffler I've tried, was quite at low throttle settings but noisy under heavy load. This is the quietest going up hill.

Both the neighbors and my wife are relieved.
 

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H

Hive

Guest
I Will Likely Join

you on the "X" muffler club.

I will put one last silencer together just for curiosity sake, however. Will be my third.

None really worked well, but will see on the latest version - PVC can like yours, but vertical.

Thanks for information.

Will report in warm weather.
 
K

kerf

Guest
After putting 7 - 8 hundred miles on the glass pack I decided to go a different direction. The glass pack quietened the 460 a good bit but the glass would get oiled soaked and required repacking and I wanted more noise reduction. I decided on a large expansion chamber with a baffle tube outlet. The body is a disposable O2 bottle with copper inlet and outlet fittings nickel-silver brazed on. The baffle tube is 1/2" hard copper with 30 5/32" holes and it is removable for tuning and cleaning. So far my test have shown it to be much quieter than the glass pack and performance seems very good. I've only run it up to 30 mph and will require some more testing tomorrow morning. I'll hit some hills and push the speed between 45 and 50 to see if back pressure is a problem. If so I'll add more holes to the baffle tube.
 

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Happy Valley

Active Member
Joined
Jul 13, 2008
Messages
1,723
Kerf, nice clean build on that mod.

Couple of questions:

What did you use to connect the stock muffler to the new chamber?
How long did you make the interior baffle tube?
And, think an evacuated propane cylinder would work?

TIA
 
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K

kerf

Guest
Thanks,


1. Silicone exhaust tubing from DDM.

2. ???, about 7" inside the chamber, eyeballed it.

3. Yes but don't blow yourself up. Make sure tank is empty and use a small nail set to drive the Schrader valve into the tank. Purge several times with compressed air before cutting.
 
K

kerf

Guest
Paint is hardly dry and changes underway. I added 24 more holes to the baffle tube, seems about right, hi temp thread sealer and safety wire to the baffle tube nut. Pretty sure I'll drop 3 or 4 mph top end but I don't run over 40 anyway. At thirty, the wind is a sweet sound!
 
K

kerf

Guest
Well, the results of this mornings run are in and many things have changed. First off, the muffler has dropped top end performance to about 9600 rpm on the flat. Plug color is on the dark side of normal so I could lean out and pick up a little but I see no need. My normal operating range is 5000 to 8400, thats 20 to 35 mph and only a few times did I run the engine to 11,000. Thats faster than I want or need to go. On the plus side, it dropped the torque curve down and more into my normal range. Lower end performance is actually better than with the glass pack. The best change is the sound, much quieter, more like a Vespa or some such scooter. With the secondary disconnected and the engine at idle, you couldn't carry on a conversation beside the bike. Now at 30 - 35 mph the wind in my ears is my new friend.
 
H

Hive

Guest
Muffler

Big muffler and I know it does the job.

To be honest, big is not what I need on my little t-3300. I want to keep it simple.

I bought and will soon test Briggs and Stratton muffler that has threaded pipe end and post the findings (eBay).

It is relatively small 2 x 5 inches or so, and vertical mount along the starboard rack leg, but I will bet is does not quiet the acceleration exhaust noise much...

If it does function, will post pics of assembly attached. It was very easy to rig...
 

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K

kerf

Guest
It may work, others have used them with success. My engine is LOUD, once while swapping stock mufflers, I cranked up w/o the muffler. It was the kind of noise you really didn't want to be around let alone ride. With only the stock muffler, riding my bike gives me a headache. Makes me unpopular with the neighbors. Back in my youth, a friend had a Honda 50 with a megaphone on it (we were dumb then), you could hear him 2 miles away.
 
L

Large Filipino

Guest
I'll keep an eye on this,Hive. The quieter I am on the bike trails the better I'll be.
 
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