Slight muffler mods, did I go too far or not far enough?

Discussion in '2-Stroke Engines' started by yoothgeye, Jun 24, 2010.

  1. yoothgeye

    yoothgeye New Member

    What was I thinking modding my muffler before even installing it? I guess I was thinking I wouldn't do it once I started riding.

    Anyway, I have an eBay (LEB) kit, standard 68.5cc kit, cheap. I was looking at the muffler the other day, roughing up the chrome with sandpaper so I could spray it with some grill black high temp paint. There was stuff inside it making noise, so I opened it up. It was just a little welding slag, so I dumped that out and decided to see how this was made. I just drew this picture from memory, so forgive me:


    I didn't want to go wild on it, so I was looking for any little thing I could do to open it up a bit. With both ends off I looked at the 2 tubes that go through the baffles and are crimped on the ends. I thought the holes drilled in them were too small, so from the tailpipe end I stuck a long screwdriver into each tube and twisted until I opened up the end of each tube. Not fully open, only about halfway.

    I thought this would free flow a little bit more, but still keep the noise down, and it's reversible with a pair of needle nose pliers.

    I have searched and seen so many different muffler mods here, so how does this one weigh in?


  2. professor

    professor Active Member

    For noise, you would have been better off adding more drilled holes near the ones you show, opening up the crimp gives the sound a more straight shot into those pipes. My preference is free flow mufflers and more than one. Only it takes up some more room.
    What I saw here that I really liked is twin stock mufflers!
  3. yoothgeye

    yoothgeye New Member

    The center section is only removable if I had ground out the 2 spot welds holding it in, then I could have drilled more holes, but I would have had to get out the welder and spot it back in. I didn't want to get that deep into it.
  4. james65

    james65 Member


    I enjoy your motovation, but wishl you had waited until you had the bike on the road. This way you would be able to make a good comparison. To really do that, you would have to wait until your motor is broken in. Seems to me that after about 40 hrs. of running your motor, it will be broken in. You will see a great improvement when it is broken in.
    That is when mods to the muffler ect. can be trurly be judged. Sounds to me that you are the type of person that will enjoy this hobby.

    Attached Files:

  5. yoothgeye

    yoothgeye New Member

    Anything with wheels, you are right.

    I was pretty sure that if I put it together and started riding I'd be having so much fun that I wouldn't want to go into the muffler and do anything, but since I'm sitting at home waiting on parts I had time while watching tv to pull it apart. If I want muffler mods later I will probably just buy another cheap stock unit and modify it.

    I have already wrapped mine in exhaust wrap, so to take it apart again would mean unwrapping it. It looks cool enough that I probably won't mess with it.
  6. motorpsycho

    motorpsycho Active Member

    here's what i did with my stock muffler.
    I put an expansion chamber on first of all and that in itself made a big improvement.
    but, i put the stock muffler on the end of the exp. chamber because the chamber with no muffler was obnoxiously loud (and i like loud).
    i took my stock muffler apart and removed the cateletic peice that was in it. then, i drilled 3 small holes in the disk that the baffle pipes are welded to. i did npt modify the baffle pipes at all because they already have plenty of holes in them.
    i took off the end cap that has the little outlet pipe in it, and i pulled that little pipe off.
    I cut the end of the muffler case at a 45 degree angle, and then i stuffed the end cap up inside the muffler case so it looks like a big open pipe at first glance.
    this mod works great and it's easy to do. it isn't too loud, but it is slightly louder than stock and it sounds like a 2 stroke dirt bike now. adding the muffler to the expansion chamber added a little more bottom end torque because it give a little more backpressure.