Would this pocket bike tuned pipe work?

tylerlough

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May 28, 2008
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Mishawaka, IN
ebay pocket bike muffler Looks like it would work if I mount it upside down from what is shown. I would cut the pipe and have it welded to my current header. Just want to get an opinion before ordering. Someone said the best header length is about 12 to 13 inches, correct. $36 seems like a good deal.
I'm ready to take my HT Moon Dog's performance to the next level. I already trimmed the piston skirt and lowered the intake port floor. The main mod is 33 tooth sprocket but I need a little more power to take greater advantage of it. Then comes the tricky part, getting it to run well with it's increased thirst for fuel.
 
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reg454

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Jan 11, 2009
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If the pocket bike had around the same cc's as the motor you are currently using than it should work with some minor modifcation.

For a power curve biased toward maximum output, the lead-in pipe's length to the expansion chamber should be between 6 - 8 times the diameter on the exhaust port. - excerpt from "Do You Really Want To Know About Expansion Chamber?"
Their is a thread here somewhere I remember reading it that has a link to this article that you can download and read yourself.

Or you can read it here I uploaded it to a file storage service.

http://www.fileden.com/files/2007/9/24/1456741/do_you_really.pdf
 

Home-made J

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Sep 16, 2008
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Santa Cruz, CA
you shouldn't trim the piston skirt AND lower the intake port...The port will stay open too long and blow back your compression through the carb. Unless you're gonna put a reed box on it, you should do one or the other...doing both will result in a loos of power...big time.
 

tylerlough

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May 28, 2008
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Mishawaka, IN
I have a 67cc motor and that pipe is made for a 49cc, is that close enough to get any improvement in the 5500 to 7000 rpm range. I'm happy with its power as is, but for less than $40 it's hard to say no.

Home-made J, I didn't lower the port more that a tenth of an inch, so I hope that isn't a big problem. I was mainly cleaning up the casting flaws.
 

reg454

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Jan 11, 2009
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I have a 67cc motor and that pipe is made for a 49cc, is that close enough to get any improvement in the 5500 to 7000 rpm range. I'm happy with its power as is, but for less than $40 it's hard to say no.

Home-made J, I didn't lower the port more that a tenth of an inch, so I hope that isn't a big problem. I was mainly cleaning up the casting flaws.
If the exhaust port diameter is the same their should be no difference, if it not then you will have to do a little work like cutting the lead tube off of the new expansion chamber and weld on the lead in pipe from the old exhaust. But I am sure that it will be just fine but you might have to use the mounting portion of the old exhaust to mount the expansion chamber.

Read this article it's good knowledge
http://www.fileden.com/files/2007/9/24/1456741/do_you_really.pdf

You might not understand alot of it but it gives you a good idea on the % of room you have to work with.
 

reg454

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Jan 11, 2009
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Very interesting.

Keep us posted on how it works out, I need an expansion chamber exhaust, but dont feel like dishing out more than I paid for my whole MB.
It's an investment of all the gas you will save from driving your car. Look at it this way you only need to buy one expansion chamber if your old motor goes out it doesn't really cost that much to rebuild them. Me father is a small engine mechanic and I grew up working on motors. But if it does go out you will not have to buy a complete kit because you already have what you need a new motor is only like $70. For the SCSW pipe $130 w/shipping is not a bad price. I'm using my tax refund this year to build my bike and I will have a lot left over. I'm getting the "80"cc kit and 36tooth sprocket from thatsdax, the SCSW pipe and the bike i am getting is $118. total cost of the build is $439.99.
 

tylerlough

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May 28, 2008
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Mishawaka, IN
If you take you take the baffle you will most likely need to change to a larger jet or drill out your current jet. With no baffle mine will misfire (due to lack of fuel) at full throttle.
As for the intake you could drill a few holes but it is not necessary.
 

JoeJ

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Jul 22, 2008
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Winston Salem NC
Yes, It will surely work I used this one from Performace pipes pocket bikes mid bikes 47cc cag Daytona Cateye models X1 X2 super bike apc X7 2 stroke gas engine pipes #190-19 and didn't even cut it down, used the original muffler (cut it down right before the weld of large part) Turned it upside down and welded it after rotating new chamber so it got close to the top bar of bike frame and mounted it with supplied bolt/rubber/washer by the brake mount on my Schwinn Jaguar fits close to the frame on top and runs ot the back on a upward angle past the seat... Jaw dropping improvement on torque and abot 8 mph top end with a 44 tooth....Just be CAREFUL The CHINA Header Pipe is so thin I burned a hole in it while welding it .Start off at a low setting if using arc welder..I would suggest a wire feeder if available to you or oxy/acctelyne using coat hanger wire to weld with. I wrapped my pipe with HI Temp header tape so I wouldn't burn my leg..Works great. doesn't look too bad either. sorry I don't have any pics.

Performace pipes pocket bikes mid bikes 47cc cag Daytona Cateye models X1 X2 super bike apc X7 2 stroke gas engine pipes
 

tylerlough

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May 28, 2008
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Mishawaka, IN
Glad to hear the pipe worked good for you. I believe I'm going to do a low mount for the pipe. I may just use the muffler that comes with the pipe because the stock muffler seems fairly restrictive. Thank you for sharing your experience with welding, I'll have a friend do the welding. I would ask you to post a picture of your bike but I know you're new to computers, so I won't ask.