For the past 3 months I've been rebuilding this little XR250 engine as as way to fill my time and keep in touch with the "real world". A world where the correct parts are ordered, the correct parts arrive and the correct parts fit straight in without having to grind, cut something off or even remake a whole new part because the ordered one was rubish. Oh, the wonderful world of metric tolerances and neatly machined parts... Not my weekday world , though.
This engine, bought in the land of the "that'll do" was taken to a workshop because it wouldnt start. Someone threw the piston in the wrong way around and that made it touch the exhaust valves. In the process of solving this (in theory, a pair of valves would be enough) I found a badly pitted and worn out cylinder sleeve, clutch basket teeth randomly removed and later found at the bottom of the sump, worn out camchain and tensioner, stripped M10 cylinder head threads and many, many other annoying little problems.
I do like to get things done at first time and I do spend time trying to find causes for future problems. In other words, fixing things that aren't broken. We'll see how long this one will last without breaking down.