In the photo below you can see a large red hose running from the sump to the oil tank. This is the motor that had the first reed valve sump breather in 1985 (Mk2 engine cases #307659) . The reed valve was mounted at the bottom of the hose. It was one of many experiments and it went through many changes including using a BMW reed valve (I used to work at Sumners Suzuki/BMW in Fresno – now closed). As far as I know this was the first reed valve ever mounted on a Norton. This photo has been in the JSM Norton race manual since it was copyrighted in 1984.