Two cycle two cylinder with rotary disk valve

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Well-Known Member
HMEM Supporting Member
Oct 9, 2009
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Been working on a 2 cylinder version of the single cylinder two cycle that I finished sometime last year. I finally finished it and got it running to my satisfaction. It runs great and starts easy with the drill drive starter.
As with everything I build it evolved along the way and runs far better than the single cylinder I built with the same concept. I think I need a bigger flywheel on the 1 cyl. I will provide drawings for anyone interested as soon as I get them cleaned up. The first rule I learned as a tool designer was that the ultimate punishment a toolmaker can do to you is to build your design exactly as it is drawn. Therefore, the drawings need a little TLC since the design changed during the build process as I made improvements.
I'll make a video of it running when I get a chance to start it outside. My wife informed me there will be no more engines running in the basement. It is a little loud with open exhaust and stinks since I run it on model airplane fuel.
I would suggest anyone that wants to build it to scale it down to 1/2" bore rather than the 1" bore I built. Hopefully a smaller scale will be less expensive material wise and would run fine.


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  • 2cyc2cyl.pdf
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