Crankcase breather pipe

The copper tube was resilient and reliable  and could be bent to lube the chain if you wished. Rubber would perish and would need to be restrained to avoid getting chopped up in the chain. Your choice.

I have had the pipe in a few positions ,Best to get rid of engine fumes  , Mine currently runs to the oil tank as I was  fed up with oil pools . But thats not ideal  , may try a reed valve as it can help reduce internal pressure and leaks.

I cut mine short and then used oil line with a PCV (positive crankcase ventilation) valve in-line, fitted behind the chaincase. I exit the oil line on-top of the rear mudguard but behind the number plate so that any drips are well away from the rear tyre.  It works very well.

My PCV valve is in addition to the rotary disc on the end of the cam.  I was going to fit an oil catch can too, but couldn't find one I liked or find a good place to fit it - so I just dump on the road :)

Far better to have the breather pipe sending oil vapour to your rear chain than just letting is suffer from rain/road dirt and whatever. Almost as good as a Scottoiler and more reliable and much cheaper. Don't believe what's said about dissolved acids being bad for your chain. If the oil vapour was that corrosive, your engine wouldn't last 5 minutes.

By the early 60's it went to the "froth tower" on top of the oil tank. Tidier than running it along the bike. Doesn't seem to lead to problems.

I put mine into a "Froth Tower"  ,but since then have  struggled  to keep the oil tank clear of mayonase ,  Short running time probably the big issue.

My breather emits mayonnaise after a short run and personally I wouldn't want that either in the oil tank or on the rear chain as it obviously contains water.

I thought I had had a brilliant idea when I routed my breather to very close to the rear chain, wrong.

I was shocked to find half the oil in the tank had disappeared in a few days due to the depression felt around the hole in the re-positioned breather pipe. It certainly did a good job of oiling the chain the rear wheel and ... .

The tank is an aerosol tin donated by my wife, the clips were from a hardware shop.  With this system the catch-tank can easily be removed for emptying.  As already stated in this thread, the timing disc must be left in situ otherwise the camshaft could move sideways.  For it to be really effective you need to drill some holes on the inside of the crankcase into the tunnel between the disc valve and the crankcase breather outlet.  The holes allow the gases to escape via the one-way valve to the catch-tank on the piston down stroke.  On the up stroke a vacuum is produced, in the crankcase, helping to keep the oil inside the engine.  Since doing this mod my engine has been practically oil free on the outside..

Cheers,  Peter J Maple  

My 99 has the later oil tank with the oil separator tower. Norton obviously listened to the owners. The oil tank breather/overflow is ducted to the top of the chainguard, giving the rear chain some welcome light lubrication on long, hot runs. It has the other advantage that if your bike has wet sumped at all, on start up the oil goes to the oil tank and not over the garage floor. Worth looking out for a later oil tank if you get the chance. 

ive modified mine and routed mine into the oil tank then moved tank breather and routed over the chain . works well. i have 3 breathers into my oil tank (1 rear crank 2 rear rocker cap 3 timing cover ) .