More on quiet

Discussion in 'Rack Mounted Engines' started by kerf, Jan 9, 2008.

  1. kerf

    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.

    Attached Files:

  2. Hive

    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.
  3. kerf

    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.

    Attached Files:

  4. Happy Valley

    Happy Valley Active Member

    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?

    Last edited: Aug 9, 2008
  5. kerf

    kerf Guest


    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.
  6. kerf

    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!
  7. kerf

    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.
  8. Hive

    Hive Guest


    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...

    Attached Files:

  9. kerf

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

    Hive Guest


    I am with ya Kerf and Large Filipino.

    I was young too and thought dual pipes and glass-packs were the rage.

    Noise sucks!

    Just came back from test ride.

    Alas, another scrapper.

    If anything, the engine exhaust sounded louder. So, am removing the rig and have finally figured out there is no simple way. Will live with the noise. It is a small engine, not all that loud, but better if muffled.

    As a matter of fact, I think much noise comes from the small opening near the muffler extension plate, and does not go through muffler.

    I give up.
    Last edited by a moderator: Aug 10, 2008
  12. Hive

    Hive Guest



    One last try coming up.

    Noted lots of carbon on muffler (Tanaka muffler) So, I am thinking I do not have good seal at exit pipe and going to retry with silicone hose.

    Have to order some, so it will be a week or so. I lost my only long piece of hose.

    A brief cobble seems to indicate it does quiet the annoying exhaust purr that my T-33 makes - the bigger motors need more silence power. No way they could run without good set of earplugs and waking the dead.

    Will report in a bit.
    Last edited by a moderator: Aug 11, 2008
  13. Happy Valley

    Happy Valley Active Member

    Following this thread with interest. I've got a 40cc Mitsubishi waitng to be installed. That's a new (but older model) 40cc Mitsu engine not the sweet and quietly updated 43ccTLE.

    You guys have probably been here before but I'll put it anyway....secondary scooter pipe.

  14. Hive

    Hive Guest


    The little pipe on the link is a chromed plated version of the $3.99 Briggs muffler I bought on eBay. The Briggs versions have threaded end that works with copper ends, however, making install easy.

    Next week or so, will know for last try on this version.

    Just want to kill the loud 2-cycle chatter a bit, without ungainly visual and physical contraptions.
  15. vegaspaddy

    vegaspaddy Member

    cant wait to see if that muffler works for you, i have one of them sitting on a shelf in the garage, and eagerly await your findings before i go ahead and buy some silicone hose.
  16. kerf

    kerf Guest

    OMG, baffle tube failure, copper tube cracked, snapped like a dry twig. A little steel tube, a little grinding, a little welding, back in business.
  17. Hive

    Hive Guest


    Paddy, am back from trip.

    Will be giving it test ride later today.

    If it does work, concern will be with direct hose connect to exhaust port and melting. May have to remove cage and the port and silver soldier a 3/8 copper pipe and/or elbow to the exit pipe, which I have been trying to avoid doing...
  18. Hive

    Hive Guest

    Muffler - Experiment Progress

    As always, I only post material and advice I have actually tried.

    Here are three pics from this latest and my last attempt to quiet this Tanaka-3300 motor's exhaust chatter.

    Frankly, I really do not like the muffler set-up as ugly etc, but if it quiets the chatter, I might stay with it. It is small and out of way. Of course, copper can be used (soldered) instead of silicone hose I used to get set up and for ease in experimenting.

    I had already drilled a small hole in cover to access the screw clamp inside the cage opening, but removing cage makes the process easier. If it does work, hole will be needed, unless elbow is soldered to pipe. It seems hose will always be needed at the first or top connection, however.

    At this point, I can start motor and push muffler on to exhaust port. There is slight difference and at this point not worth the time and effort, etc. Under power is big question.

    The engine fan system does make noise, but the idea is to quiet the loud chatter when power is applied. Unfortunately, the Tanaka port leaks. You will note a slit in the last pic, (blue line is hard to see) slit inside the cage opening on left as viewed.

    At idle, exhaust is visible coming from slit and adjacent area- where the part fits on to Tanaka stock muffler. Under power, surely noisy and under pressure.

    Will try fiberglass to block. I think the area gets too hot to use Permatex gasket materials. Will remove cage, and the pipe/ screen part to use glass to seal hole which will be held in place by replacing exhaust port part. May try to seal edges also, but careful not to let glass foul the arrestor screen.

    Also, the hose shows signs it may not stand up to heat, in which case one must silver solder or weld a 3/8 copper elbow to pipe and that may be going too far for the little change that we may get. Will see how the seal works first.

    Appreciate working input.


    Attached Files:

    Last edited by a moderator: Aug 20, 2008
  19. Hive

    Hive Guest


    Here are pics of today's tricks.

    First, it does reduce the chatter - a little - which is noted when assy is removed and replaced, while motor running.

    Is it worth the trouble? Not really. Will ride it as is for day or so and tell all y'all - plural.

    Anyway, I installed fiberglass around insert to seal slit, which you can see in pic 2.

    First pic is dirty exhaust port, from leaky hose etc. I think engine was running for number two pic.

    Pic Three: loose muffler assy.

    Ran motor and noted exhaust coming out a bit. It could be from that area or from where muffler attaches to engine above...probably a bit of both. Looks like stock muffler is not perfect picks up some of the exhaust and scatters it through cage, etc.

    Will let you know later what happens and what I learn.

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    Last edited by a moderator: Aug 21, 2008
  20. Hive

    Hive Guest

    Muffler - Experiment Progress

    Final word on final experiment. For a "Tanaka-3300," this muffler attempt is not worth the time and inconvenience. Need bigger tank like Kerf's.

    The intent was to build smaller muffler to reduce the harsh chatter when opening up throttle and although it does remove some of the chatter, when at full bore, the muffler I used (little Briggs and Stratton) is too small to alter the chatter that much.

    Maybe a modified Briggs and Stratton can might work, but then the whole thing gets too complicated etc, at least for me, so will settle with the noise as is ... but Kerf's successful project has got me thinking ...

    Glad he kept at it.

    Those running larger Tanaka and Mitsubishi engines and similar versions will have to use the larger versions noted on the forum, like Kerf's, using longer chambers etc.

    And I sympathize with their need to solve quieting problem. Quiet is best, particularly where the laws are somewhat ambiguous regarding motored bicycles or where neighbors prefer quiet, which is most everywhere.

    If someone does more experimenting and gets a significant and satisfactory result, by all means post it.
    Last edited by a moderator: Aug 26, 2008