In order, on the video, piped saw 4.0, stock saw 5.85, then two more, but close to a knot, piped 5.7, stock-8.15.
stock saw with ported muffler 7.9, piped 5.6 bogged a bit, and 5.5 higher revs.
The piped saw is 16 months old, and was woods modded by Ed Heard. It is running 16 inch bar/3/8th chisel, half round ground and half square--I forgot to square file the first half--new chain just a bit dulled.
Stock saw is 16 inch bar, and .325 chisel, round filed (more)
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Depends on the size of the cuts as to what saw is best for crane work. Most of my saws are modded, so a smaller size will cut fast and handle a longer bar. The 5100 will easily pull a 20 inch bar, and would handle a 24 as well.
If the trees are larger, I prefer a modded 372 or 7900, 24 to 32 inch bar.