Universal Expansion Chambers

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
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:
 

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bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
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.
 

BobbyT

Member
Mar 16, 2014
162
14
18
Santa Maria ca.
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.
 

BobbyT

Member
Mar 16, 2014
162
14
18
Santa Maria ca.
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.dance1
 
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bairdco

a guy who makes cool bikes
Aug 18, 2009
6,549
238
63
living the dream in southern california
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.
 

BobbyT

Member
Mar 16, 2014
162
14
18
Santa Maria ca.
Thanks Baird,
This is the 2nd ex chamber I have got from you. They work Great! Cut the stock muffler off shove it on, tweak it where you want it and presto more power! going for a sixty mile ride today to break in a new engine. These things work great on a stock engine with my .003 copper head gaskets. Chumash Casino anyone?
 
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mobike91

Member
Sep 14, 2010
111
2
18
lebanon, oregon
Bairdco could I PayPal you and have you ship me one to Oregon? I'd love to tinker with a better expansion chamber than I got. I also am hoping to make it out to Cali this year for some racing in October! If that's where your taking about lol.
 

CroMagnum

Member
Sep 2, 2011
148
1
16
Los Angeles
Baird is still on the loose.
He was at the May Willow Race and will be at the upcoming Sat Oct 21st Grange race.
He just does not come here now cause he does not like using this forum on his phone.

I really can't blame him for that. As I get older I can't see crap on my phone either. TV ads for stuff like Jitterbug phones and Depends start to look more appealing every day. And I'm seriously thinking about buying The Clapper. ;)

Maybe Baird will take all his Expansion Chamber money and buy a laptop. :D