rg123

Looks like top of cam chain guide broke off, cam chain has worn a gouge out of the side of the casing from the head to the base.I have the sides off the when i took off stator side i found the flywheel was loose... theres evidance of past damage to head, valves and cam seem ok.next problem is the siezed/rounded oil drain bolt.. can i try flush out the bottom end with diesel or something or what checks do i need rather than opening the crank cases?

am going to look at a sr250 laterthis week, if the bikes had it may try shoehorn the engine into the 125

Hi all ,just picked up a sr125 for my Gf bought cheap as spare repairs. Put a battery on it and i has a clunk when turning over..def not wanting to start. Gave it a quick compression check showing 80psi Took cover off oil filter and it is covered in thick mettallic paste so something in there has been grinding away. My question is where do i start looking, obviously its a major .are there common faults on these bikes? If it helps the girl we bought off said it was running fine and she sold to some young guy who took off down the road then turned up half hour later saying it had stopped running so she gave his money back and sold it off for nought Any guidance or ideas on my next move appreciated.