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Post by gingel on May 5, 2015 18:07:04 GMT -5
Hi, I have a SYM 125cc which i rebuild the engine and also finished the engine break in. The original exhaust which made over 100k KM is making a rattle noise (it started to rattle before the rebuild). I bought a replacement exhaust, unfortunately it was not a perfect fit from the begining. Where i bought it, they bent the pipe a little on a bench vise until it fitted the bolts holes, but the center stand leg is touching the pipe. I tried to find a used exhaust, but didn't find one. Anyway, i wondered if is it possible to cut open the old exhaust and fix it? Where do you need to cut it? at the middle or at the end? Here is a picture of the old exhaust:  Thank you. |
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Post by jerseyboy on May 5, 2015 19:02:11 GMT -5
I would cut the end where the seam is,,since you will have it open you should make some mods to the baffle,,make the holes a bit bigger so it free flows,,then install UNI Pod and upjet,,that motor will love you,it will sound alot deeper also!
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Post by wilds on May 6, 2015 0:02:42 GMT -5
I had a similar muffler and cleaned it out so that it became free flow. There are several chambers in the muffler so I had to cut it at both the back and the front and then make a cut along the muffler from the front to the back to get it opened. There is a pipe that winds back and forth inside the muffler which makes the exhaust pass each chamber. On my exhaust system there was also a small catalyst mounted on the pipe inside the muffler... I ripped everything out and welded a 2" exhaust pipe right through the inside of the muffler. Finally I mounted my own "DB-killer".  |
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Post by jerseyboy on May 6, 2015 6:20:17 GMT -5
I had a similar muffler and cleaned it out so that it became free flow. There are several chambers in the muffler so I had to cut it at both the back and the front and then make a cut along the muffler from the front to the back to get it opened. There is a pipe that winds back and forth inside the muffler which makes the exhaust pass each chamber. On my exhaust system there was also a small catalyst mounted on the pipe inside the muffler... I ripped everything out and welded a 2" exhaust pipe right through the inside of the muffler. Finally I mounted my own "DB-killer". If you drill a few rows of holes in that 2" pipe around the entire circumference&length then pack fiberglass around the outside of the pipe that will get rid of most of your crackle db(without losing any flow, your damper does look a little restrictive to me) and cause more of a deep thump,,I've built many free flow exhausts and if you duplicate a glass pack they work well as the glass deadens the sound that gets forced through the holes pretty well and still allows full free flow through the pipe:) |
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Post by hunter on May 6, 2015 10:55:32 GMT -5
A local muffler shop has good prices and I was considering having them make me a custom exhaust for my scoot and using a 12 inch glass pack on the end. How well would that work or would it even work?
The main reason for this is I cannot seem to find any bolt on exhaust kits that I KNOW will fit my scoot. Don't wanna spend that much coin only to have it not fit, so I was considering this as an alternative.
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Post by gingel on May 6, 2015 14:30:48 GMT -5
Actually i just want to fix that rattle noise. i don't want to change the inside.
So, cutting it where i marked it in the picture will allow me to take out what is inside
and make repairs?
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Post by wilds on May 6, 2015 23:33:25 GMT -5
If you drill a few rows of holes in that 2" pipe around the entire circumference&length then pack fiberglass around the outside of the pipe that will get rid of most of your crackle db(without losing any flow, your damper does look a little restrictive to me) and cause more of a deep thump,,I've built many free flow exhausts and if you duplicate a glass pack they work well as the glass deadens the sound that gets forced through the holes pretty well and still allows full free flow through the pipe:) I can promise you there is no restriction at all. That little valve at the backend is so I can set it so it gives some backpressure (and keeps the noise down). Maybe I should've mentioned that it has a pipe that looks like this inside:  and it's filled with muffler fiberglass, otherwise it would be too loud... This is how the whole system looks like:  The header pipe is a step-up type and it starts from 19mm and is stepped up to 28mm to 30mm to 32mm. That is just so the exhaust gases will have room to expand on the way out. |
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Post by wilds on May 6, 2015 23:49:35 GMT -5
Actually i just want to fix that rattle noise. i don't want to change the inside. So, cutting it where i marked it in the picture will allow me to take out what is inside and make repairs? If I don't remember wrong you want be able to see into the muffler because of the "chamber wall" at the back. I suspect that the rattling sound you hear is one of the tubes that runs between the chambers because which is loose. But if you are lucky it could be that last pipe at the end of the muffler and you will see it and be able to weld it back again. Here's a good video of how it can look like inside: |
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Post by jerseyboy on May 7, 2015 6:33:00 GMT -5
Actually i just want to fix that rattle noise. i don't want to change the inside. So, cutting it where i marked it in the picture will allow me to take out what is inside and make repairs? If I don't remember wrong you want be able to see into the muffler because of the "chamber wall" at the back. I suspect that the rattling sound you hear is one of the tubes that runs between the chambers because which is loose. But if you are lucky it could be that last pipe at the end of the muffler and you will see it and be able to weld it back again. Here's a good video of how it can looks like inside: That guy did a good job stripping that muffler out,,sounded great when he was done. |
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Post by gingel on May 7, 2015 15:24:39 GMT -5
Actually i just want to fix that rattle noise. i don't want to change the inside. So, cutting it where i marked it in the picture will allow me to take out what is inside and make repairs? If I don't remember wrong you want be able to see into the muffler because of the "chamber wall" at the back. I suspect that the rattling sound you hear is one of the tubes that runs between the chambers because which is loose. But if you are lucky it could be that last pipe at the end of the muffler and you will see it and be able to weld it back again. Here's a good video of how it can looks like inside: I hope it's the last pipe at the end of the muffler. When you shake it, you can hear something is loose. |
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Post by wilds on May 8, 2015 7:35:00 GMT -5
You see how much he had to cut...
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