But they weren't supposed to be oil tight either - that came with the California smog rules...oil leaks are hydrocarbon, one of the emissions tightened up. Cars and bikes ran breathers into the open, called a road tube because it directed oil onto the road. My Norton was totally leak free, but it was a well looked after bike....all the other stuff was well abused, damaged by thugs with screwdrivers and hammers, and parts from different models in one bike. It wasn't hard to make a late model British bike leak free, just attention to detail, but an older model will never be leak free because that was never the intention.
I've just fitted a PCV to the Norton, theory is it keeps the crankcase pressure low so the oil hangs around instead of trying to escape. Rode to the WOF place. funny on old bikes, they are so busy going " oh that's a nice bike" they check bugger all. Went for a 30 minute ride, no cough as they don't really do that..... The mirrors are clear and no vibration as Mr Isolastics seem to do the biz. Might go for a ride up SH 16 tomorrow...
PCV (positive crankcase ventilation) is a loop system, hooked into the intake manifold, and won't really work on a bike unless it's built for it....the PCV valve just works like a reed valve, flowing one way and not the other. I've taken the plumbing off the BMW, so it doesn't send oil and crankcase fumes into the carbs....no oil pumping out the hole yet.
Hows the Norton after the 200km ride this avo has it stopped its dripping when parked issue I only saw a puff of oil out the exhausts once on the whole ride
My first real road bike was a 53 Matchless G9. Once I'd replaced the seal behind the magneto it was pretty reliable. I put a concentric carb on (the monobloc was worn out) and gave it a valve grind which led to its only major failure - I couldn't get 500 head gaskets so used 650 ones. One of the gaskets failed going up th Rimutakas and the hot gas melted a pushrod. But by then I was seduced by shiny Jap bikes, sold the matchy and bought a new 72 Kawasaki F9 Bighorn ($1169) - great while it was going but it broke down a lot. Magneto rotor came off several times, rotary valves caught in the inlet port and the shrapnel destroyed the piston, etc. Shoulda kept the Matchy.
I had a '53 G9, and was most certainly the worst bike I've ever owned. I had a mag problem and fitted a distributor....but the generator was stuffed, and you need a charging system to run a dist. The breather was on the end of the crank, and pumped oil into the chaincase, so the clutch slipped with too much oil - I took the chaincase off and it never sealed again, so the oil just leaked out now. The breather couldn't cope with the pumping, so the generator acted as a supplementary breather, and oil poured out of that too. Putting a 500 twin into a 350 single frame wasn't a good idea, it really handled bad. On the plus side, the engine was by far better engineered than the other British twins - I liked the separate barrels and heads, and the eccentric tappet adjustment is the best ever...in the world, by far - so simple, so easy. I don't think I ever crashed the G9, which was rare for me in those days....I must've been pretty freaked out by the handling.
