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Joined: Dec 10, 2016 18:10:15 GMT -5
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Post by rmadrid20 on Dec 10, 2016 21:46:39 GMT -5
Hi guys and thanks for visiting my post, I have a gy6 scooter that needs new muffler and I have the dilema of which to buy cuz seems the the issues are the brackets and I don't want to buy something that won't fit the bike. Not looking for performance parts just a good muffler, maybe later I'll start modding the scooter with a performance in mind, attached there's some pics of my scooter Looking in eBay and amazing or any other place, thanks guys a lot for your input   |
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Post by wheelbender6 on Dec 11, 2016 10:51:32 GMT -5
The stock pipe is very heavy (relatively) and costs about as much as some after market pipes.
I would still go aftermarket unless you don't want to rejet the carb.
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New Rider
Currently Offline
Posts: 2
Likes: 0
Joined: Dec 10, 2016 18:10:15 GMT -5
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Post by rmadrid20 on Dec 11, 2016 10:53:00 GMT -5
Has been really difficult for me to find one, do you know if eBay has one that fits this scooter? Or any other website?
Thanks
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Post by cyborg55 on Dec 11, 2016 14:21:16 GMT -5
Parts for scooters ,, scrappy dog ,, or martins mopeds will be a big help ,,,
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Post by wheelbender6 on Dec 11, 2016 17:26:53 GMT -5
I know scrappydog sells a few varies for the GY6.
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Post by oldchopperguy on Dec 12, 2016 0:09:27 GMT -5
Welcome to the site!
Even though these GY6-powered scoots are pretty much alike, I'm amazed at how different the exhaust systems are from one to another. It's often difficult to get a "bolt-on" direct replacement. You may find one by looking at pix of the muffler, but if not, it's not hard to rig up some kind of mounting. I've found the actual muffler doesn't make a great difference in running. Even stock muffs are not all that restrictive. It's the HEADER that needs attention for optimum running. The stock headers are usually SMALLER inside diameter than the EXHAUST PORT in the head... Duh...When the muffler on my Chinese 150 went south, I made a header from a John Deere generator header and flex-tubing. Here's an old photo showing the difference in inside diameter...
You can buy full-diameter headers and use most any muffler. Or, for simplicity you could use a grinder and open up or "Chamfer" the stock header at the port to ease the exhaust flow. That simple mod should actually make a noticeable improvement in running.
For a new muffler, I used a "chamber" pipe from a 50cc which ran great. Here's a pic of the setup, mainly to show you can make a mount to attach just about any muffler with just hand-tools... 
I'd go with the least-expensive muffler, and make a simple attachment mount from strap-steel, or aluminum bar-stock if necessary. But while it's apart, I do recommend at least smoothing out the header where it meets the head, or, if feasible in the budget, replace the header with a full 1" inside diameter performance pipe. Hope this may help...Ride safe!Leo in Texas
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Post by pistonguy on Dec 13, 2016 21:18:55 GMT -5
K there Chopper dude. this is your former neighbor from keller. I'm sure I've seen you at Willhoits or Johnny Esparzas place. I know you have some smarts but what in the heck are some of you doing with a Two Stroke exhaust system on a Four Stroke? The Cone's are of different Angles and Lengths, along with the Mid section For Scavenging, Different angle cones and lengths are to make power either Down Low or Top End along with the Stinger on the end were the Silencer is attached. The back pressure is also to build a certain amount of heat mediums and and working sound waves. I just don't get it  |
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Post by pistonguy on Dec 13, 2016 21:21:05 GMT -5
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Post by pistonguy on Dec 13, 2016 21:32:45 GMT -5
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Post by pistonguy on Dec 14, 2016 6:55:14 GMT -5
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Post by cyborg55 on Dec 14, 2016 9:48:14 GMT -5
I've seen guys/gals running 2t exhausts on 4t engines,on a few forums over the years,,,
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Post by pistonguy on Dec 14, 2016 14:45:45 GMT -5
I've seen guys/gals running 2t exhausts on 4t engines,on a few forums over the years,,, Oh I've seen it. I even see some of theses systems Falsely marketed as Four Stroke Exhaust. If one understands how each systems works its silly to put a Expansion Chamber Two Stroke exhaust on one. We would see the Pipe Gods at Pro-Circuit and FMF doing so if it was worth a snit. |
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Post by cyborg55 on Dec 15, 2016 9:17:47 GMT -5
Basically what's going on with most generic old timey pipes and silencers is a brooklands setup,,,altho now the can is packed with glass wool with a perforated interior tube inside,,,removing restriction and tube length is the more important issue,,,the new thought mini expansion chamber helps a bit ,,,,I got super lucky with my dr,,,
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Post by pistonguy on Dec 16, 2016 12:41:32 GMT -5
The Stinger on the end is to build back pressure, the purpose for the back pressure is to build a certain amount of Heat, the purpose of the Heat is That the Sound Waves work much better in a Higher Heat Medium, this not only helps Pull out the Exhaust there is a fair amount of crankshaft rotation or Duration that Both the Exhaust Port and Transfer Ports are Open, The Sound Waves also Pull in more Intake Charge. The GY-6 is Most happy with as little back pressure as possible. so Im still calling bunk to a Two Stroke Expansion Chamber on a Four Stroke GY-6. it will run but not as good with a pure free flow setup. Here are a couple images of the Latest in Four Stroke Pipe Technology from the Pipe Gods   |
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Post by oldchopperguy on Dec 16, 2016 14:32:39 GMT -5
The Stinger on the end is to build back pressure, the purpose for the back pressure is to build a certain amount of Heat, the purpose of the Heat is That the Sound Waves work much better in a Higher Heat Medium, this not only helps Pull out the Exhaust there is a fair amount of crankshaft rotation or Duration that Both the Exhaust Port and Transfer Ports are Open, The Sound Waves also Pull in more Intake Charge. The GY-6 is Most happy with as little back pressure as possible. so Im still calling bunk to a Two Stroke Expansion Chamber on a Four Stroke GY-6. it will run but not as good with a pure free flow setup. Here are a couple images of the Latest in Four Stroke Pipe Technology from the Pipe Gods
Back in the day... (early sixties) we raced karts. Soon, the expansion/contraction pipes replaced the shorty straight-pipes on our McCulloch and West Bend 2-stroke kart motors. They indeed are tuned for a specific rpm use, with the air/fuel-charge being pulled THROUGH the cylinder and partially into the chamber, then RAMMED back into the combustion-chamber for a minor, but true "supercharging" effect. A 2-stroke will run best with the chamber-pipe at its proper rpm. I still remember the window-breaking scream of a trio of methanol-burning McCulloch MC10's at full-song at my back... Whew! Be still my beating heart! Now, the chamber pipes WERE a lot quieter... Dang...
But, when we understood the way the chamber-pipes worked, we learned by experience that they would also improve performance on a 4-stroke... NOT by the complex pulling and ramming of the charge, but by the brain-dead-simple reverse-venturi effect of the first part of the chamber pulling the exhaust from the cylinder. Period. It's not MAJOR like with a 2-stroke, but it's there, and, far better than a straight-pipe OR low-restriction muffler. You could get the same effect with a megaphone exhaust, but... THAT is LOUD... and offers no back-pressure. The engines do require SOME back-pressure for good running, but not much.
Trust me on that one... My old 150 GY6 had a noticeable improvement in idle, throttle-response and WOT performance with the 2-stroke chamber pipe. It worked on our old Briggs and Cushman Eagle flatheads, and just as well on the GY6 OHC motor.
It's a totally different phenomenon than with a 2-stroke where the chamber pipe actually interacts with the intake as well as the exhaust... On the 4-stroke motor, the chamber pipe simply scavenges the exhaust slightly better than either a muffler OR a straight-pipe. It's the reverse-cone first-part of the chamber that helps scavenge a 4-stroke. On my old 150, I experienced better overall performance, AND easier tuning with the chamber pipe, just like I did with archaic 4-strokes of the 1960's. It really DOES work... Honest!  Try one for yourself, and I don't think you'll be disappointed! Ride safe,Leo in Texas |
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