I had to rebuild my motor because of crackes in my cases, mine where around the crank seal, at first I got the crackes welded up this was about 8 years ago, it was pretty hard to weld there as the case around the seal is not very thick and there was so much oil coming out of the poras of the alloy when welding, the welding was done by a very skilled trades man and good friend, I was his T/A for over 13 years, but after rebuilding the motor when I fired it up for the first time it was still leaking, was so frustrating after all the time we spent welding and machining the case to find it still leaked, the Norton sat for a few years out of frustration, but while it sat I chased up a set of good cases and a lot more performance parts for the motor.
After a few years and when I had the urge to work on it again it didn't take that long to rebuild, the new second hand cases have sealed up well and don't leak a drop of oil, it fired up first kick and has been back on the road now for 18 months now, I ride it 6 days out of 7, I am glad its back on the road but should have not let it sit for the time it did because of frustration over the ordeal, but I did have another bike when it was off the road which helped, I have owned my Norton since new so it means a lot to me, as for the orginal numbers who cares as I know inside the new cases it still has most of the orginal parts and what caused the cracks, young and silly and too many burn outs, but now older and wiser but still young and silly in the mind :lol:
Ashley