This is what I didn't realise, that the fumes could come back out as well. Nasty blighters. I'm glad I asked now and thanks for the answers. I can get the engine breathing setup better.
If I leave the tappet chest breather open to the elements then where should the rocker cover connect to: (a) the tube on the underside of the air filter housing so that the fumes are filtered, or (b) the pipe on the side of the carburettor (where the tappet cover pipe is currently connected) so that the fumes are not filtered?
You need this type of carb - with the brass breather connection - sticking out at ~ 10 o'clock. Poor alternative - is the connection on the side of the air filter - which has poor suction, and plasters the filter with oil........... which soon blocks it![frame][/frame]
It this a hs2 su carb(the pic that BMC posted)Is it a 1 1/4" carb I need,Would I need any other parts to get the breathing sorted,Different oil filler cap,hoses or pipes???