So I got this project done and it wasn’t too bad. The worst part was tapping the 1/4” holes in that very hard cast lobe. It was slow, tedious and nerve wracking, expecting the tap to snap off in the crank at any instant. Next time I’ll definitely buy a solid carbide tap.
I had to add counter weights to balance the bare crank so I could spin it at a decent rpm in the lathe. That was done on the same homemade stand. Pretty easy and accurate too.
I used a 3/16” plate for the weight, which I knew would be too heavy, but the plan was to mill it down slowly to fine tunes the balance. I ended up taking .33” off the plate which took it from 100 grams to 80 grams. So in the end I’ll be adding three ounces to the crank to get to the recommended 50% balance factor.
It’ll be a few weeks before the engine is up and running, but I’m pretty curious to see if it makes a worthwhile difference.
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