A few of the Man-Cave crew aren't happy with their Black Widows' performance, so I bought 6 sets of parts to upgrade them as close to Venom status as I can. I got Killer Cranks, TD cylinder/pistons, and the washers that go between case and drive washer to prevent galling when using a power starter.
Tonight, I polished the Killer Cranks by threading them onto a 5x40 length of threaded rod, chucking them into a drill press at low speed, and wrapping oil soaked 800 grit around, and letting it run for about 30 seconds. Visible improvement in the finish! I took it easy, but may go to 2000 grit for final fitting.
Note, you do NOT lap a crank into the case, the case is anodized, relatively soft Aluminum, and you ONLY want to work on the crankshaft to achieve a good fit! Only the anodizing provides a hard surface to withstand hard use; cut through that and you are doomed to short life.
Next up will be dis-assembling the engines and cleaning all the parts. The fit of shaft to case is a major component of performance, so there may be some mix and match and re-fitting going on.
Sadly, the pistons and cylinders are not taper ground, nor tight enough to fake it.
More as it happens.