Damn, damage or has someone made the hole on purpose? that part of the bike should be pretty damn tough and out of the way of most things that can damage it... Haven't done much lately, tried to pull the selector drum and forks out of "blue's" gearbox with little luck, the machine screws holding in the retaining plates don't want to budge. Also discovered the bottom case has been dropped at some stage, landed on the corner of one of the case bolts, pushing the mating surface out and cracking it a bit, will need to be machined flat again, maybe a spot weld to seal the cracks up before machining... Just dropped the crank out of my other project, the SR500. Who needs a ten ton press when you have a dozen blocks of wood and a hot air gun?
Small update - found a place that can check my frames, now I just have to find a shipping company to get them to Sydney.