Query Approved

if ur block/piston is spoilt just remove the old one and replace it with a new kit and change what all necessary,u say about the connecting rod size being different,ur bike is running on that same stock crank for such a long time u need to just change the rod only if there is a big play in it or else its fine,good that u bought a new crank as u can keep it for future use,spares are an issue for RX100.
u have a new block/piston set a new crank chk up the clutch plates,pressure plates,and finally the bearings if reduced life then change the engine bearings,besides this there is nothing major in the engine gear wheels are not an issue i guess.