Here's a flame licker I built a few years back. It's Dr. Senft's "Poppin".
To my mind, it looks pretty good. However, it just doesn't run. Ball bearings instead of bushings, several tries at a piston using different materials, ditto for the inlet valve, warming the cylinder, re-timing forever--all to no avail.
I recently obtained a nice graphite bar, so I'll try another piston.
This thing is an ongoing source of frustration....
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