Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Motorized Bicycle Mechanical Components > Intake & Exhaust

Intake & Exhaust The ins and outs - carburetors, manifolds, mufflers, expansion chambers and more to keep your engine running the way you like

Reply
 
Thread Tools Display Modes
  #1  
Old 03-20-2017, 02:13 PM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,314
Default Universal Expansion Chambers

I'm making some pipes designed for 50-80cc engines, that are clamp-on universal pipes.

The idea is, you just cut the can off your existing pipe, slide on my chamber and clamp it on to your header pipe.

I'll be making some straight ones, and some angles ones to fit a variety of bikes. Some bending of your header pipe may be required.

Still in the prototype stage, and I'll be bringing some to the Grange race on april 1st.

Once they're proven on the track, they'll be for sale (and a thread will be posted in the appropriate section.)

Here's a sneak peak:
Attached Images
File Type: jpg 20170320_114852.jpg (168.9 KB, 43 views)
Reply With Quote
  #2  
Old 03-20-2017, 09:43 PM
BobbyT BobbyT is offline
Motorized Bicycle Elite Member
 
Join Date: Mar 2014
Location: Santa Maria ca.
Posts: 147
Default Re: Universal Expansion Chambers

Good idea Baird. I'd like to try one. Look's good!
Reply With Quote
  #3  
Old 03-30-2017, 03:28 AM
BobbyT BobbyT is offline
Motorized Bicycle Elite Member
 
Join Date: Mar 2014
Location: Santa Maria ca.
Posts: 147
Default Re: Universal Expansion Chambers

Baird,
I have a motorized bicycle ready to test the ex chamber. See you There!
Reply With Quote
  #4  
Old 03-30-2017, 10:32 AM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,314
Default Re: Universal Expansion Chambers

Cool. I'm finishing up a bunch today that I'll be bringing to the track.

I built my china racer back up and put one on it. And it works great.

My bike's all modified, and I didn't have a stock pipe, so I don't have a base to guage the before and after performance gains.
Reply With Quote
  #5  
Old 03-30-2017, 11:02 AM
BobbyT BobbyT is offline
Motorized Bicycle Elite Member
 
Join Date: Mar 2014
Location: Santa Maria ca.
Posts: 147
Default Re: Universal Expansion Chambers

I will load up some extra pipes to cut. Will have stock pipe on so we can see the difference. I can only bring 3 bikes. One will be a crash test dummy!

You can join us for dinner Friday night if you like pork adobo and rice. I'll be pitting with Rebel Bikes. I'm slowly loading up want to get there this afternoon not to late.

I need to find some tires on the way.
Reply With Quote
  #6  
Old 03-30-2017, 11:23 PM
Cylon's Avatar
Cylon Cylon is offline
Motorized Bicycle Elite Member
 
Join Date: Jun 2015
Location: Maine
Posts: 298
Default Re: Universal Expansion Chambers

Very nice looking pipe.
Reply With Quote
  #7  
Old 04-03-2017, 05:36 PM
BobbyT BobbyT is offline
Motorized Bicycle Elite Member
 
Join Date: Mar 2014
Location: Santa Maria ca.
Posts: 147
Default Re: Universal Expansion Chambers

I tried the pipe at the track Sunday. I ran it on my daily driver with a mostly stock 69cc China girl.
First mounted directly to header pipe, ran smoother but no noticable power gain.

Neil suggested a longer header.
I used a 12" high heat 3/4 id. hose for next test.
With length at 13 1/2" total mounted down the center between crank. Good tork and speed with this setup.
Tried it on one of the race bikes and it worked good.

I am going to use this pipe on my daily driver from now on.

I recomend others try this pipe it sounds good and it's not loud.
Reply With Quote
  #8  
Old 04-04-2017, 09:52 AM
bairdco's Avatar
bairdco bairdco is offline
a guy who makes cool bikes
 
Join Date: Aug 2009
Location: living the dream in southern california
Posts: 6,314
Default Re: Universal Expansion Chambers

That's good to know. Header length is a big factor in where the power band comes on.

On my race bike, i tried a few different lengths, and a 6" header gives my bike a wide range of power. Instead of having that sudden, "on the pipe" feel, I opted for a wider powerband to deal with that hill at the grange.

I saw a lot of bikes hit their power band near the top of the hill, and I wanted mine to be more gradual.

Not that it helped, with the multitude of other disasters my poor china girl was having. (And, y'know, crashing in the moat left by the drift cars didn't help.)

My calculations come out to about a 10-11" header for the band to hit right before peak rpm.

As always, results will vary.

If I can rebuild the clutch guts on my motor, I'll do some more testing.

Thanks for the honest input, bobby.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 07:46 AM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com