Yeah, I Hate them springs, I just broke a spring on my highly modded Cag 16:1 A2. Have to take the body off to get the housing off. Going to clean up the holes the springs grab to make them last longer.
Clutches too, on one engine had to pull the flywheel split the cases and pound the end on the crank to get it off the clutch, it was glued on, the new clutches are keyless. I just cut a slot in a stock clutch a few weeks ago as a test for doing the 2 two shoe racing clutches on my twin engines. I used my air hacksaw, I love that and the air file, and disc cutter, makes a hard job easy,lol.
On My Hot Rod red head engine, the only power tools I used was my 8" bench grinder to ruff cut the round lip for the Cag B/B alloy head to sit on the 49cc cut piston port cylinder, and files and sandpaper.