49cc's on a Schwinn

FOG

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Mar 3, 2019
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In post #155 I mentioned putting holes the back of the piston to feed the boost ports. But one of the PB guys, and what would I do without them, suggested slots instead.

DSCF0941.JPG


I like that a lot better than a couple of holes.
 

FOG

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Mar 3, 2019
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As usual I'm goin' off the deep end again by making my own cylinder head. I dunno why. Because I can I guess ... :)

Compression ratio is obviously a big issue but I have this incredible resource at my fingertips we call the internet. I've always wondered what the correct way to calculate CR on a 2 stroke was, and now I know you have to take into account when the exhaust port gets closed.

And there's a calculator for that ...

http://www.torqsoft.net/compression-ratio.html

Luv the net.

Using that a 3cc chamber yields 9.38 to 1. Now I just gotta figure what dimension it takes to make a 3cc chamber. Back to the net ...
 

FOG

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Mar 3, 2019
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I found an online calculator for the volume of a dome which led to this ...

40mmCylHead.jpg


All that stuff on the right side is for the wee little cutter I gotta build next. I just kinda eyeballed the 1st one, no drawing, and it won't cut the combustion pocket without runnin' into the squish cut. :( It's good down to a radius of an inch or so but I need to reach in there and cut a 5/8" radius for the combustion pocket.

DSCF0943.JPG


That cutter ain't cuttin" in that far. Too big.
 
Mar 11, 2017
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Salem Oregon
NICE BEAUTIFOLD BUILD, FOG! Excellent choice of color, and yours is the first build I've seen using the Pocket-Bike Motors that are all over Ebay for cheap! Smoother/better that a China Girl? Inquiring Minds want to know! Keep up the amazing work!
 
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