I bought a brand new '69 125. Great bike, fast, light, more power than any other 125 available then.
Woodruff key holding the mag rotor on the shaft split repeatedly.
Condenser mounted under same rotor would overheat so if you stopped the bike on a hot day after a hard ride it would not start for an hour.
1981 Moto Guzzi V50 III (being cafe'd)
2007 KTM 450 EXC
1960 Lotus 7 (hey, it's a 4 wheel motorcycle!)
1953 Matchless G80 trials