Restoration adding modifications, butchery or?

I admit it. I did Fred's OB crankcase mods to my 72 the last time I stripped the engine. I can't speak to all the other posts about the pros and cons of different breather systems but after careful study of the tech article on Old Brits I came to the conclusion that the process would benefit my Commando. And it has.

I am not an engineer or a machinist but I know a good looking breather when I see it. Back when I worked on Nortons we were also a BMW dealer. The Airheads have a built in breather at the top of the crankcase. It has a small metal breather disk that opens when the pistons move in compressing the crankcase gasses and closes when the pistons travel out. I knew that the Norton would benefit from this treatment.

The crankcase sump mods also made sense to me although I never considered trash getting into the oil pump a concern. Maybe I should have, I don't know. The results are an oil tight engine (for the most part) and believe me the bike oiled itself pretty handily before the modification. I continue to ride the Beast and I have to say the the last thing I worry about out on the road is the OB crankcase mods.

BTW, It was a beautiful winter day here in Texas with a big blue sky, cool but not cold and plenty of sun. The Norton had a blast and so did I.

Hi

I used the XS breather in the magneto position. Didn't touch the cases, I just cut the allen heads to a v shape. Scribe the magneto hole onto an alloy sheet, measure the bolt centers on the breather (remove the bracket it comes with) & place it so that the breather is upright. I found you can cut the bolt heads so that it fits without shaping the cases.

Chris