"Machining" liners, crank shafts and crank cases free hand can be done. The ideal tool would be like what the jeweler's have, a stationary high rpm motor with a flex shaft that is about 3 feet long. Probably really expensive. A cheap pneumatic die grinder that can accept 1/4" shaft tool bits would be plenty if you have a good air supply.
You must figure that little mishaps like losing your grip on the piece is bound to happen, so duct tape everything that isn't going to be modified. Avoid clamping parts unless you can make cylindrical holding fixtures to protect them and to avoid distortion. Scribing cut lines on liners can be challenging on the nickle or chrome, so paint the area with a magic marker to high light your scribe marks.
Be light handed with the cuts and maintain the same level of patience and force as if you were doing dental work on your daughter.
opening up the crank shaft bore can be done with a wood dowel and 40 or 50 grit sandpaper. Take a hacksaw and cut a lengthwise slit in the dowel, then insert a scrap of sandpaper into the slit. Now you can hog out the crankshaft. This will test your patience, so just tackle the project in shifts and it will eventually get done. Trying to do it with a long rotary file is tricky and much harder to keep the hole concentric.
A real machinist might detemper the crank then drill it, then retemper it...or else drill the crank in it's natural state with a very expensive drill bit at just the right speed and amount of pressure.