1- Swingarms rusted out where the axle locating plate attaches to the body of the swingarm on the underside.
2- Frame rusted out where the footpegs mount up. Also check the sidestand mounting plate.
3- Rear wheel hub flogged out with loose bearings
4- Butchered fixing holes/threads for the mounting of the exhaust flange on the cylinder.
5- The obvious one, cylinder on it's last oversize
6- Non standard RM or year specific parts (ie: forks were rooted & replaced with PE or later RM parts)
7- Main bearings that have flogged out the cases.
8- The main Suzuki disease, welded gear and kickstarter shafts
9- If the gear lever is not welded the check the chain has not worn through the shaft.
10- Badly corroded & dented fuel tanks
Plastics, rear shocks, seat cover/foam & consumables are easy, they just cost $'s