Expansion chamber , but needs research & development

D

djase10

Guest
Hi All
Now that i have my Gasless MIG welder,
i can weld thin steel
without the worry of BLOWING HOLES through the work!!

Time for what i have wanted to do for AGES ..

Develop a cost effective expansion chamber..

SO....

Bought a cheap pocket bike expansion chamber,
& cut it up,
& welded it together so to fit a HT 48cc..

Results are ..
without muffler ==TOO Loud , bottom end power increase ONLY,
LOST top end power ..
with muffler
What a beautiful sound it has, it almost sounds like a 4 stroke thumper.
lovely exhaust note, louder , but not Aggressively loud..

sounds & looks the part ..

BUT, as before
= BOTTOM END POWER ONLY.

So------- some further research & development is required..
A pleasure to do ..

Yes i could have bought a BETTER pipe to start with, but $75 JUST to cut up and see what happens isnt in my book..

Only cost me $10. for the pipe i used..

Jase
 

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Mountainman

Active Member
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up top mountain -- Sourthern Ca.
nice job of fitting and welding there

with your slight loss of power -- guess the dimensions are off a little ?

there is some good information floating around -- you are getting it -- NICE WORK

ride that MB thing
 

fastboy9

Member
Local time
11:14 AM
Joined
Jan 22, 2008
Messages
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Location
essex, england, UK
your header pipe determines where abouts the power band is, at the moment it sounds like yours is pretty low in the rev range. This is because your header pipe is long, the shorter the header pipe (the pipe before the expansion chamber) the higher the power band will be, i.e. more top end. The longer the header, the more low end power.

Its just all about getting the right measurements, to experiment I used some silicone tubing and hose clamps for a header, then adjusted this length until I got what I wanted.

There is a good software program that you can download for free, that does all the dimension calculations for you: http://www.bevenyoung.com.au/mota.htm

Hope this helps!

AndyInchVille on this forum has designed and developed a pipe, maybe you should try talking to him?

Fastboy
 

QuadManiac

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Local time
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Aug 17, 2008
Messages
76
Location
San Diego, CA
Neat program, but have any idea what most of the parameter values (port diameter, etc) would be for the standard HT engines, so we can get a start without tearing it down and measuring?
 
D

djase10

Guest
Bottom end acceleration ehaust pipe:)

Hi All

RESEARCH & DEVELOPMENT can be a tedious and laborious process ,
BUT
Also results can be achieved instantly & by accident ..


The result of the pictured pipe is GREAT for bottom end performance !!

I extended the pipe with an OLD SEAT POST of all things, TACKED them in place & then
tested it rigorously last night ,

WOW ..!!
= dramatic acceleration curve ..

with a 44 Tooth sprocket, it is SIMPLY fantastic at bottom / & MID end PUSH.

TOP SPEED was in turn reduced to 45km/h,

BUT that was of no concern BECAUSE it felt QUICK...

SO , i will leave this expansion chamber AS IS ,
( welds / fractures tidied up first, to fix some cracks that developed during testing),
and Hang it up to be used accordingly..

This story will continue....

Ride Safe ALL..

Jase
 

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D

djase10

Guest
Rear vision mirror from KMART

Hi QuadManiac
I like your mirror placement. How'd u mount it? Less vibration than at the handlebar end?

The mirror is a clamp "around" type, ,
i have it clamped on the top of the forks using a cable tie.

Pretty much stays where it is,
& just have to move my leg out a bit to have GOOD REAR VISION.

Jase
 
D

djase10

Guest
Latest expansion chamber build.

Hi All

Here is how my latest pipe went together..

Used part of original exhaust manifold.

Pic 13 & 14 are the final result.

Looks & Sounds GREAT,

I cant tell any Power gains as yet due to heavy weather,

THIS PIPE ==To be continued.

Jase
 

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Local time
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Messages
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Treasure Coast, Florida
I have been playing with the length of the stinger and found that the size and length can make major differences as well as the header length. I have a pipe like you are using, and I added a smaller/ longer stinger to the end, and it made a major difference. I believe the design of these pipes is VERY mild, looking at the long thin cones and the lack of any kind of belly.
 

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