Breather Pipe (listed in Norton 1948 Spare Parts catalog as Pressure Release Pipe) and 1/4" BSP union nut to fit bevel chamber of all SOHC models (30/40, M30/M40 etc).
These pipes are made from good quality copper and then nickel plated to give an excellent satin finish very similar to the original. The bend shape and ferrule profile are almost identical to originals (please note - obviously these engines were made for many years, and the profiles did change slightly from year to year - but I took this profile from a pipe I believe to be original).
These pipes were listed as fitting the front bevel chamber (some engines did not fit them though - look for a breather union at the rear of the top bevel chamber face - just behind the magneto chain housing) - however, they can also be used on the front crankcase breather in front of the barrel (left of right) if your engine was fitted with a front breather.
Note: front breather unions are most common on magnesium SOHC racing crankcases, and can be found on either the left/drive crankcase, or timing side/right crankcase - the 350cc pre-war M40 racing crankcase shown in the photo unusually has two breathers! Therefore, fitting this U-bend breather pipe is useful for attaching a length of black 3/8" bore breather oil pipe (sold seperately - see Item 0634) to re-direct engine oil vapour down to the bottom of bike onto the road.
Fitting this breather pipe (and black rubber oil pipe if you wish to do so) adds that finishing touch of originality to your motorcycle - I do it with all my bikes. And obviously - if you are using your Norton in competition events - you will have to fit these pipes feeding into a 'catch tank' to pass scrutineering.