1973 Honda CB750 Custom Build Episode 11

This week I notched the cylinder skirts so that the forged aluminum rods can clear them during rotation of the crankshaft. I used a Bridgeport milling machine and a radiused end mill to do the job. I followed up with a small grinding stone on a Dremel too to chamfer the notch and eliminate any rough edges that might harm the piston.

The depth of the notch ended up being 8 mm with a width of 28 mm. This allowed the forged aluminum connecting rods to clear the cylinder skirt by a little over 2 mm.

cb750 forged aluminum rod clearance

cb750 cylinder notch measurement

cb750 cylinders notched

cb750 cylinder notch chamfer

Here’s this week’s video showing the whole process.
Keep on hackin…

EICO Model 147A Signal Tracer

I found this signal tracer at an antique festival here in North Carolina. The festival is a yearly event and there always someone there with some vintage electronics. As I was walking around the event this piece caught my attention. The seller wanted $20 for it, I offered $15 and we struck a deal. It’s in great condition and it still works quite well.

EICO (Electronic Instrument Corporation) was established in New York City in 1945 by radio repair business owner Harry Ashley to manufacture electronic test equipment in kit form. Their first product was an audible signal tracer.

In my research on this piece I found some good info.

Owner’s manual

Instruction manual

Info page on radiomuseum.org

Vintage signal tracer info

This week’s video.

Keep on hackin…