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Post by gy6fandan on Aug 9, 2014 16:22:01 GMT -5
Rather than pay for expensive and much louder performance / gutted free flow muffler I thought this modification in the gasket area between the header pipe and muffler may be ok ? Because a cylinder head with bigger intake and exhaust ports would require the additional venting of spent fuel. Aside from louder, I don't know what the performance pros and cons would be by having exhaust venting in two locations on the same line (push and pull effect). 1 Minute video of the idea here : MUFFLER MOD FOR VENTING EXHAUST BETTER |
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Post by scotttx on Aug 9, 2014 16:52:47 GMT -5
your muffler has rivets, drill them out and go to town on the guts of that thing then screw it back together.
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Post by gy6fandan on Aug 9, 2014 16:55:04 GMT -5
After I remove the rivets what should I do to it ? - is my mod idea no good ?
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Post by alleyoop on Aug 9, 2014 17:34:20 GMT -5
Its ok, it will sound like it is leaking someplace, just as long as it does not backfire on you because now it also will be sucking in extra air from there not only exhausting.
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Post by scooter on Aug 9, 2014 21:41:15 GMT -5
Did you say the hole would be pointing down? If so, that might be a fire hazard. It's nice that you can take yours apart. Mine is welded together. I like mine quiet though. If I knew of a cheap and easy way to do it, I'd make it stealthy. I like peace and quiet. A bunch of noise "harshes my mellow".
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Post by scotttx on Aug 9, 2014 22:24:16 GMT -5
just look for ways to make it more free flowy. I have no idea whats in there so you'll have to figure it out.
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Post by pmatulew on Aug 10, 2014 8:48:26 GMT -5
Look up Challenger Space Shuttle Disaster.
Venting exhaust out of what is essentially a leaky gasket isn't an ideal solution. The hot exhaust gasses flowing through the restricted opening will quickly burn up the gasket and the hole will be bigger than you intended.
At best is will sound like the exhaust is leaking. At worst the gasket will fail and you run the risk if overheating the engine from running too lean.
With that generic aluminum can muffler I would be more inclined to modify the guts of it.
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Post by gy6fandan on Aug 10, 2014 18:18:56 GMT -5
Seems like the gasket material was rated at 800 - 1200 degrees. So I am not too worried about the material failing due to heat but I plan on keeping tabs on the way it wears. + the space shuttle fuel supply is different then regular gas... But thanks for voicing the concern too me.
I also have cylinder head temperature gauge that is installed between the spark plug and the head
As far as a "fire hazard" ? I do not understand how having the exhaust venting towards the ground would start a fire / be a fire hazard - any explanation how it would be a fire hazard would be appreciated.
**** Alleyoop mentioned air being sucked back in - that was the negative effect I seem to have heard somewhere in the past concerning the hole in the muffler gasket between the header pipe and muffler. With the new cylinder head with bigger intake / exhaust ports I was told I needed to vent the exhaust better. Although I am still using stock 24mm carb "PD24J - Keihin style". Re-jetting / tuning is in the process along with a new carb needle that has the movable clip for finer tuning.
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Post by oldchopperguy on Aug 12, 2014 12:06:27 GMT -5
Over the 7 years I had my Xingyue 150, I experimented with most EVERY phase of the engine and tranny.I found that the actual muffler made little difference in performance, but... The HEADPIPE made a major difference. Most GY6 150's have headers SMALLER than the EXHAUST PORT in the head. And you now have an even-larger port in your performance head. This constriction RIGHT AT THE PORT is not a good thing. The best performance I ever obtained (along with appropriate carb-tuning, better CDI, coil, etc.) was by making a header with an inside-diameter as large as the exhaust port... Please see pix below...  For a muffler, I turned to an old go-kart trick from the 1960's, and used an expansion/contraction-chamber exhaust from a 2-stroke 50cc scoot. While the expansion/contraction setup will NOT "supercharge" a 4-stroke, as it does a 2-stroke, it DOES scavenge the exhaust even better than a plain straight-pipe, and without all the noise... LOL! It's also FEATHER-LIGHT, removing MANY pounds of un-sprung weight. On washboard roads and railroad crossings, I could REALLY feel an improvement in handling. Stock exhaust systems are HEAVY. This setup was EXCELLENT on my GY6, but honestly, the muffler is less important than the header. Your setup should run OK, but I'm slightly uneasy with the new "hole" so close to your head. You don't want cold air sneaking into the header on a hot motor. No matter your muffler setup, I'd be sure to have a large-enough headpipe to allow the head to "exhale" freely. Gutting the muffler can help, but even stock muffs are not all that restrictive. At least not as restrictive as the undersized header.
Hope this may help...Leo in Texas
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Post by oldchopperguy on Aug 12, 2014 23:39:14 GMT -5
Gy6fandan,
I replied to your request on exhaust info, hope it helps... Any questions, just ask... It reminded me also, that I made a cooling-fan scoop-extension that really helped my air-cooled scoot in above 100-degree temps. This also might be good for you...  The chrome scoop is the typical unit off eBay, the extension I made from PVC tubing, covered with chrome tape...    This extension places the scoop out PAST the plastics, and out of the vortex they create. This gets the scoop into fresh air, and lowered my oil-temp by about 20 degrees if I recall... From "dangerous" to "OK". Not necessary below  degrees or so, but VERY effective above 100! It's pretty easy and inexpensive (and also looks cool as all get-out)... LOL! Ride safe! Leo in Texas (where it's been around 105 for two weeks!) and glad my current ride is water-cooled...
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Post by alleyoop on Aug 12, 2014 23:51:19 GMT -5
Very nice mod Leo with nice pictures and explanation, functional and looks really cool to boot, You should put this in the TIPS and TRICKS section.
Alleyoop
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Post by oldchopperguy on Aug 13, 2014 11:31:41 GMT -5
Very nice mod Leo with nice pictures and explanation, functional and looks really cool to boot, You should put this in the TIPS and TRICKS section. Alleyoop
Thanks Alleyoop!
Both the exhaust and fan-scoop extensions were posted in detail, long ago, but I never thought to put them into the tips and tricks. I'll do that when I get a chance... Gotta find all the pix, and strain the old memory bank for details.
In all honesty, I'm SO spoiled now with old, watercooled 250cc "Minnie Mouse" being as reliable and trouble-free as a Japanese car that I don't often think about the constant fixing and sweating blood to "get the scooter right"... But I learned SO much through 7 years of wrenching on my old aircooled 150 that I often peruse the 50-200cc aircooled section to offer advice I learned the hard way, to guys and gals still "on the Chinese learning curve".
Both these mods REALLY did bring ASTONISHINGLY good results. The large-diameter header and 2-stroke exhaust REALLY amazed me, by smoothing out idle, and making carb-tuning MUCH less "iffy", and combined with a UNI air-filter and no-limit CDI, Bando coil and iridium plug, I finally had snappy acceleration, good torque and top-end. For the record, all the carb, and ignition mods were already in-place. It ran pretty well, but not quite "optimum". The new exhaust simply "pulled it all together".
I'm absolutely convinced that stock exhaust headers being SMALLER diameter than the exhaust port are a MAJOR contributor to the difficulties we often encounter while trying to get the carb and ignition "right". If I ever again get a Chinese GY6, the FIRST thing I'll check out is the exhaust header BEFORE making ANY other changes... LOL!
The fan-scoop extension did far more than I would have expected! I can't remember from my earlier post the exact difference in oil-temp, but I did a high-speed run on a 100+ degree day with only the fan scoop. I checked the oil temp and it was something like 230 degrees. I then added the extension, performed the same ride, and checked the oil-temp and I believe it was around 205 degrees. I'll see if I can find my original post for the exact details.
Suffice to say, getting the cooling air from OUTSIDE the "hole" in the air caused by the floor-plastics REALLY cooled down the motor. Just the scoop alone lowered the oil-temp by a few degrees over no-scoop, but extending it past the plastics did wonders! And it's such an EASY mod!
Thanks for all your advice on so many subjects! You're one of the "old-school-experts".
Ride safe,
Leo
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Post by gy6fandan on Aug 13, 2014 14:40:11 GMT -5
Oldchopperguy ---> Thanks for the help with the PM you sent me. I am looking into materials / prices for the mod on the exhaust.
I have the fan scoop on my setup but the extension you did looks like a really good idea to catch the air better.
Thanks again for the time and effort with mods and details - It is really appreciated.
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Post by oldchopperguy on Aug 15, 2014 12:26:01 GMT -5
Oldchopperguy ---> Thanks for the help with the PM you sent me. I am looking into materials / prices for the mod on the exhaust. I have the fan scoop on my setup but the extension you did looks like a really good idea to catch the air better. Thanks again for the time and effort with mods and details - It is really appreciated.
The scoop itself helps some, but it's still stuck behind the floor-plastics. By extending it out, it really gets into "fresh" air... On mine, I used a female/female connector for the large PVC pipe. IT fit the scoop, AND the fan-shroud perfectly, while the plain PVC sewer pipe was a tad small. It's best to accurately measure the fan shroud opening and bring a ruler, so you can get a piece of PVC that best fits the "hole" in the shroud. I also sanded the chrome off the scoop inside edge, and epoxied it to the PVC fitting. The exterior finish is simply chrome tape from the auto parts store... It actually looks quite "factory". Black paint would be fine though... LOL! The little aluminum stand-offs with rubber "O" rings are probably necessary for long-life, since the long screws put considerable strain on the scoop's brittle mounting tabs. It's a little more work, but may save the scoop from breaking after only a short run... Mine was on for nearly 5 years with no cracking. Ride safe! Leo |
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Post by geh3333 on Aug 16, 2014 23:11:01 GMT -5
Nice scoop , I used an PVC 45 degree elbow with one end male and the other female . I trimmed the male end and drilled holes to screw I to the fan cover and painted it flat black . It turned out really good .  . Front side angle.  . That is true , being out past the side plastic really helps . That's why I never bought the regular scoop . You made it work very good . |
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..BAD TO THE BONE..
degrees or so, but VERY effective above 100! It's pretty easy and inexpensive (and also looks cool as all get-out)... LOL!
