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Post by ricardoguitars on Jan 21, 2015 10:00:44 GMT -5
I need to change the exhaust on my scoot, the original exhaust broke as well as a cheap replacement I bought  I'm thinking if it would be better to get one of those fancy $100+ branded exhaust or have one made by a local shop, what are your opinions and/or experiences?  The price between both alternatives is almost the same. |
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Post by rockynv on Jan 21, 2015 13:04:02 GMT -5
I just welded the original exhaust back together with a few reinforcements and corrected the vibrations that caused it to fail in the first place. At a outlet the sells Chinese tools you can buy a small wire feed welder for less than an oem muffler and then be equipped to fix most any of the steel items that can fail on the bike or around the house.
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Post by alleyoop on Jan 21, 2015 13:58:53 GMT -5
I need to change the exhaust on my scoot, the original exhaust broke as well as a cheap replacement I bought I'm thinking if it would be better to get one of those fancy $100+ branded exhaust or have one made by a local shop, what are your opinions and/or experiences? The price between both alternatives is almost the same. If the price is the same Have one Made and have them use a 1 1/4 pipe. That is what I had done and it has been on for going on 5 years the muffler as well I put on a SuperTrapp muffler when I had the exhaust pipe made and fitted all looks like I just put them on and it has been almost 5 years now. |
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Post by ricardoguitars on Jan 21, 2015 15:50:32 GMT -5
Is it possible to have a non-restrictive performance exhaust that is not noisy? I like to go fast, but I hate noisy bikes  |
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Post by alleyoop on Jan 21, 2015 16:26:32 GMT -5
Suppertrapp mufflers have discs on the end of them, so the few discs the quieter the more discs more free flow the louder(WIN WIN).
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Post by jerseyboy on Jan 21, 2015 18:21:57 GMT -5
Yup,,
I noticed even 99% of the free flow designs are restricted in the first few inches from the head,,i dont know why they do that??
I will have somebody build me a 1-1/4" header sooner or later,,thats really the best way,,then you can utilize any silencer you want like a Supertrapp,DG,Two Bro's,or Yosh...thats what I would do...
My silencer if you want to call it that is only LOUD when Im hard on the fuel,,when I cruise it just thumps away,,but if I am going up a hill its pretty loud also..I like it cause when I pull up along side a Harley they look at me like,,what the heck is this thing with a funny smirk on their face,,its funny watching their face change when I pull away on them out of the hole...lmao!!!!
Not bad for a little 150...huh..lol
Most of the free flow pipes I see are pretty much a straight pipe with a drilled baffle,,the baffle is the same size as the head pipe but its got hundreds of holes drilled in it,,then they pack fiberglass around the outside of the baffle inside the silencer can to help absorb SOME of the noise,they work well.Same principal as an old skool glass pack or cherry bomb for muscle car.
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Post by scooter on Jan 21, 2015 19:15:05 GMT -5
Yup,, I noticed even 99% of the free flow designs are restricted in the first few inches from the head,,i dont know why they do that?? I will have somebody build me a 1-1/4" header sooner or later,,thats really the best way,,then you can utilize any silencer you want like a Supertrapp,DG,Two Bro's,or Yosh...thats what I would do... My silencer if you want to call it that is only LOUD when Im hard on the fuel,,when I cruise it just thumps away,,but if I am going up a hill its pretty loud also..I like it cause when I pull up along side a Harley they look at me like,,what the heck is this thing with a funny smirk on their face,,its funny watching their face change when I pull away on them out of the hole...lmao!!!! Not bad for a little 150...huh..lol Most of the free flow pipes I see are pretty much a straight pipe with a drilled baffle,,the baffle is the same size as the head pipe but its got hundreds of holes drilled in it,,then they pack fiberglass around the outside of the baffle inside the silencer can to help absorb SOME of the noise,they work well.Same principal as an old skool glass pack or cherry bomb for muscle car. The small restriction in the header has to do with pressure. It makes the exhaust expand just after the restriction and creates higher exhaust gas velocity in the restricted area. I think it is supposed to suck more air/fuel in when the intake valve opens or something like that and/or creates back pressure. |
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Post by JoeyBee on Jan 21, 2015 19:38:28 GMT -5
I'm looking for another exhaust also. But I'm finding it very difficult to find a "performance" exhaust that's not fully chromed, rainbow colored, or both.
Why do they all have to be so flashy?
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Post by jerseyboy on Jan 22, 2015 9:14:16 GMT -5
Yup,, I noticed even 99% of the free flow designs are restricted in the first few inches from the head,,i dont know why they do that?? I will have somebody build me a 1-1/4" header sooner or later,,thats really the best way,,then you can utilize any silencer you want like a Supertrapp,DG,Two Bro's,or Yosh...thats what I would do... My silencer if you want to call it that is only LOUD when Im hard on the fuel,,when I cruise it just thumps away,,but if I am going up a hill its pretty loud also..I like it cause when I pull up along side a Harley they look at me like,,what the heck is this thing with a funny smirk on their face,,its funny watching their face change when I pull away on them out of the hole...lmao!!!! Not bad for a little 150...huh..lol Most of the free flow pipes I see are pretty much a straight pipe with a drilled baffle,,the baffle is the same size as the head pipe but its got hundreds of holes drilled in it,,then they pack fiberglass around the outside of the baffle inside the silencer can to help absorb SOME of the noise,they work well.Same principal as an old skool glass pack or cherry bomb for muscle car. The small restriction in the header has to do with pressure. It makes the exhaust expand just after the restriction and creates higher exhaust gas velocity in the restricted area. I think it is supposed to suck more air/fuel in when the intake valve opens or something like that and/or creates back pressure. Well thats good to know scooter,, Kinda like the same principle as the expansion chamber on a two stroke..only way too find out if it increases performance is to test against a header thats the same size all the way through...wish I had lots of $$ and time..lol..I have neither. |
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Post by oldchopperguy on Jan 23, 2015 23:09:08 GMT -5
Ricardoguitars,
I ran into the same troubles with my old Xingyue 150. Alleyoop, and the other posters covered about all there is to know on a replacement system. Factory headers ARE too small right at the head, creating severe restriction at the port itself, which is not good at all. Some minor restriction is good, but more down the line from the head.
Many "performance" headers STILL are undersized... Duh... Some however, are very well designed. As mentioned, MOST are a little "fancy" and usually "pricey".
As mentioned, an expansion/contraction "chamber" exhaust works well (make that VERY well) on 4-strokes as well as 2-strokes. You won't get the massive supercharging effect on a 4-cycle like you will on a tuned-pipe 2-stroke, but the venturi-effect still scavenges the 4-stroke engine even BETTER than a straight-pipe. And much, MUCH quieter...
It's hard to get any aftermarket exhaust that simply bolts up to a given scooter. Most require considerable alteration as to mounting brackets, etc. so I opted to just make my own. I found a header from a John Deere, Onan or similar old flathead twin generator engine was the proper diameter and bolt-pattern for my GY6 exhaust port (I ground off the protruding flange that went inside the port on the flathead Onan engine). I made a "stub" from the steel header, pie-cutting it and bending it tighter to clear the frame, and had a shop weld up the cut closed. This is necessary to get the header to run BETWEEN the engine and the frame, factory-style. I wanted to run the pipe BELOW the frame, away from the engine, but THAT was not feasible, since it placed the header too low, making it vulnerable to hitting any obstructions like speed-bumps. I also heat-wrapped the flex-pipe header to protect the engine some, from exhaust heat. That tight clearance is probably why they use the skinny headers on the GY6's.
Then I made a connector from flex-exhaust-tubing for an RV generator that fits perfectly over the steel stub. I then connected that to "muffler" which in my case was a chamber pipe for a 50 cc 2-stroke scooter. You can find the small-diameter flex pipe on eBay or at RV stores, for generator engines. I cut and bent the original muffler clamps and re-used the neoprene insulators on the chamber housing. I made a simple aluminum bar-stock bracket, drilled to attach to the original muffler mounts on the scooter. VERY simple and inexpensive.
For a muffler, you could use a "cherry-bomb" type auto glasspack, or a Briggs & Stratton stationary engine muff, or most any smaller, lightweight muffler for a motorcycle, or stationary engine. If you can find a chamber pipe like I did (I found it hidden inside a couch at the VA thrift store) and they wanted $8 for the couch. I gave the $8 for the stainless pipe, and left the couch... LOL! Some poor guy bought it, and hid it from the missus inside the couch, and it was still there after the dee-vorss...
Here are pix from a "how to" post I did way back... If you could buy a factory performance header with FULL inside diameter like Alleyoop mentioned, it would save some fabricating, but a scrap generator header and some cutting will get it done.
The end result of this exhaust was MARKEDLY improved throttle-response, EASIER carb-adjustment and improved overall running... Starting, idle and top-end. Not to mention it looks cool as a mother-in-law's stare... I do attribute MOST of that improvement to the full-sized header, but the chamber exhaust does help, even on a 4-stroke. I learned that back in the sixties when racing 2-stroke go-karts. We tried their chamber exhausts on 4-strokes with GREAT results!
Here are the pix...
This setup ran marvelously on my aircooled 150, and from idle to about half-throttle, it was quieter than the stock muffler. From half-throttle to WOT it had a very sweet "bark"... A pretty nice howl, that shouts "I'm NOT stock" but definitely not obnoxious. Not near as loud as the stock muff on my current Kymco 250!
Hope this may at least give you some ideas on how you want to do yours... Anything you can buy, saves work, but you CAN make most stuff yourself, at least with a few dumpster-dives... LOL! The main thing is to be sure you use a full-diameter head-pipe to relieve restriction right at the head/exhaust-port. Even "chamfering" the stock, undersized header to ease the exhaust into the header helps some.
Ride safe!
Leo in Texas
PS: Also remember that the entire engine/drive-train is UN-SPRUNG weight... Anything you can do to lighten the weight of the exhaust-system dramatically improves HANDLING! This setup cut about 25 pounds off my scoot's un-sprung weight, making negotiating washboard roads, railroad crossings, etc. much more sure-footed! |
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Post by ricardoguitars on Jan 24, 2015 10:49:02 GMT -5
That pipe looks badass Leo  I wish I had a welding machine and knew how to use it That's a short term goal, I need to do some welding on my Landy too. i will show your pics to the shop and see if they can do something similar  |
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Post by oldchopperguy on Jan 24, 2015 13:57:24 GMT -5
That pipe looks badass Leo I wish I had a welding machine and knew how to use it That's a short term goal, I need to do some welding on my Landy too. i will show your pics to the shop and see if they can do something similar Glad it was helpful! I'm glad I took plenty of "how-to" pix back then. As poor as the factory headers are on Chinese 150's, I figured plenty of guys would like to see a fairly easy fix... LOL!
The fun aspect was that it DOES look pretty nasty... and we all like nasty! The BEST part however, was how the engine RAN with it!
Searching for, and finding a useable 2-stroke chamber exhaust is well worth the time. I forgot to mention you must cut off the front (header) portion from the 2-cycle chamber pipe, since it will not come close to fitting the GY6 head, and also is too small, like factory headers. I just cut it in the taper at a point where it went into the flex-pipe, and connected it with "Inferno" header patch, and a stainless muffler clamp. With the flex-header heat-wrapped, it all looks pretty good.
I do believe the secret IS the header being large enough. The muffler is really "secondary" to the process. Even the dismal factory mufflers are not all that restrictive. You can blow into them and there's no serious obstruction... If you can scrounge up a 2-stroke "chamber" for a muffler however, they DO run swell on 4-strokes. If you opt for a "factory" style muffler, They don't last forever, but look nice... you can probably cut off the muffler-mount REAR portion of the old header, attach it to the new, larger header and the factory muffler then would bolt right up. And you could also then use stock muffler-mounts/clamps.
The only kink in my setup was getting the old generator-motor head-pipe to make that VERY tight bend at the head. But the pie-cut allowed it to be bent upward, and a local muffler shop welded the cut closed for $5. I would much prefer the pipe to run UNDER the frame, with a more gentle bend, but I couldn't see a way to do so without the pipe being the lowest part of the scooter, and the first speed-bump it hit would destroy the engine.
That has to be the reason for the skinny factory headers.
I have seen true performance bolt-on stainless headers on eBay, with full-diameter tubing. They are factory-bent to fit, and would make the process SO easy... But, they're usually available only as an expensive kit, with stainless muffler, running around $200 or more. One of the members way back did snag the header only for around $40 and was very happy with it. I don't remember what kind of muffler he used, but any small cycle, stationary engine, car glasspack (even a baffled straight-pipe) or similar would work fine.
getting a cheap welder and learning to use it would be a GREAT idea. Otherwise, the local muffler shop is your best friend... LOL! The only tools I used on mine were BIG hammers, a BIG vice (to mod the muffler clamps) wrenches and a drill...
Once you have a head-pipe, only your imagination limits your choice of muffler and mounting methods... Just remember the muffler has to "bounce" with the rear wheel, and do NOT mount it to the frame. Some guys have forgotten about that, with disastrous results...
Ride safe! And enjoy making up a badass exhaust!
Leo
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Post by JerryScript on Jan 24, 2015 15:36:37 GMT -5
Hmmmm, it's relatively easy to bend pipe in a shop. It shouldn't be too hard to find examples of most stock headers and duplicate the bends for each model. Seems like a pretty low-cost low-risk proposition for someone with a shop to make some money on large ID headers for scooters.
Once again, the main issue is the end user being able to identify his/her scooter properly to make certain they get the correct header. I wonder if there is a simple universal adapter to mount headers to mufflers, with today's tech, it shouldn't always require a weld, gotta be a tape/resin solution out there.
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Post by oldchopperguy on Jan 24, 2015 20:38:02 GMT -5
Hmmmm, it's relatively easy to bend pipe in a shop. It shouldn't be too hard to find examples of most stock headers and duplicate the bends for each model. Seems like a pretty low-cost low-risk proposition for someone with a shop to make some money on large ID headers for scooters. Once again, the main issue is the end user being able to identify his/her scooter properly to make certain they get the correct header. I wonder if there is a simple universal adapter to mount headers to mufflers, with today's tech, it shouldn't always require a weld, gotta be a tape/resin solution out there. That's true, but I don't think most owners even realize the problem is the too-small HEADER. They usually think the MUFFLER is the restriction. You see all kinds of scoots with exotic mufflers hooked up to the little headers. I don't think you'll convince most riders that they need to replace the header.
To make it worse, the design of most GY6 scooters leaves ONLY about 1 1/4" total clearance between the crankcase and frame, forcing the header to bend at the head, GREATER than  degrees. The pipe can't even EXIT the head STRAIGHT, then bend at a right-angle. It has to exit at a SLANT, toward the rear. The PIPE must be welded to the flange BENT, and ALREADY ANGLED BACKWARD.
The obvious answer would be to run the header down, and UNDER the frame, but that won't work either, because the header would hit every obstruction, destroying the head, or even breaking the cylinder off at the block. Now we all know hitting speed-bumps is the job of the center-stand... LOL! And the exhaust header SURELY is glad of THAT!
 Why makers did NOT simply angle the engine a few degrees more "up" to allow a decent bend in a full-diameter header is anybody's guess, but it certainly is a major design-flaw, requiring either too-small a head-pipe, or, some clever fabrication of a better setup.
As for different scoots having different headers, that is true. I originally got a beautiful (though heavy) chrome chamber exhaust taken off a new Vento 150 4-stroke. Shipped to me all the way from Puerto Rico! I figured it MUST be capable of mounting on ANY GY6, but... The angle of the header-flange is DIFFERENT from the one on my old Xingyue. When aligned with the port, the entire exhaust aims a foot outward from the scooter! The header could be cut and re-aligned, but none of the fancy mounting tabs were even in the same county with the mounts on the scooter frame anyway, so I just made one. Easier in the long run...
I figured a short stub steel header, fused to a flex-exhaust tube would solve the whole problem, and it did. Once stuffed between the crankcase and frame, there is NOT much room to "flex" but there IS enough to align the flex-pipe with most any type or angle of muffler setup you want to use.
I definitely think there might be a market for a simple replication of the "stub" I made, by cutting a proper flange, and welding on radical bend 1" or larger pipe-stub, baloney-sliced at the weld to keep it tightly aimed parallel to the cylinder. That could then be sold with a length of flex-tubing and pair of clamps and high-heat adhesive to make a REALLY "universal" header adaptable to ANY 150.
I just don't know if the market would be large enough to support a business making them. However, they would surely be a good "proprietary" item to make and sell through a scooter shop.
What I really wish is that China would just up the displacement and technology a tad, and offer an affordable engine option like the Kymco "People 200" motor... A simple, carbureted GY6 type aircooled 163 cc engine that accelerates like a 250 and cruises 60+ mph and tops out around 70 mph. No mods needed...
Put THAT motor in my old Xingyue 150 and I'd STILL be riding it!
Ain't life grand...?
Keep wrenchin', keep ridin' and ride safe!
Leo
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..BAD TO THE BONE..
degrees. The pipe can't even EXIT the head STRAIGHT, then bend at a right-angle. It has to exit at a SLANT, toward the rear. The PIPE must be welded to the flange BENT, and ALREADY ANGLED BACKWARD.