A10gf, thanks for that. I got rid of the copper pipe only this year. The reason being I can now see the oil going to the rocker spindles and can see the colour of it too. Another benefit is, many years ago I re-ground my own crank, (yes I know!) and after about 200 miles there were more flakes of metal in the oil than in the paint! The clear pipe saved me from doing massive damage that day, seeing that tends to encourage you to push the bike home rather than ride it.