5: Why does it leak oil?

The days went by and I was busy learning to drive a bike again. It had been quite a while since I last rode a modern bike. My Nimbus cannot – and should not – be compared to a Moto Guzzi. The Nimbus is very fine for a slow ride up and down the costal road – but thats about it. I realize that other people have travelled to the North Cape on theirs but thats not for me.

A Moto Guzzi is different. When you start it, the carburettors sound a bit like a steam engine – but the roar when you open up is like music to my ears. What a feeling – revving up the engine leaving a curve and feeling the pull. I drove for longer and longer as I grew used to it. A Le Mans is not designed for city traffic – you sit too bent forward – but as soon as you hit the highway it is in its element. Something happens when the rev counter passes 3500-4000 – it becomes a totally different engine.

There are no air filters on a Le Mans mark 1 and 2. Just a wire mesh, filtering large object like stones, gulls and pedestrians.

There is no way that I would dream of putting for instance K&N air filters on mine. It would spoil some of the sound, and as I dont drive very much on dirt roads I expect my piston rings to last 50.000 km. And now that I know how easy it is, it doesnt represent any big problem to me. Others dont view it the same way – quite alright with me.

One thing I found out pretty quickly – my right hand hurt a lot. After having looked into the heaviness of the throttle it turned out that it wasnt only because of my office muscles. I ordered a couple of new springs for the carburettor at the Stevns Brothers in Haarlev. Very nice and competent people – and low prices on top of that, and quick to deliver. With the new springs the soreness disappeared right away.

A few weeks after I got my license plate, my brother in laws bike was due for legal inspection. His was valued without any problems and we started out driving together.

Brother in law and author - next generation in the background .

Talking about “next generation” – Nicklas, as the boy is called, asked me one day whether I thought if I would still be alive when he turned 18. I smiled and asked him why. Well, you see – then Id like a bike, too, and come for rides with you. Rather cute, dont you think?

One day my brother in law and I had to switch bikes, of course, and the first time I had to brake I had a shock. I was almost thrown off – his bike braked that much better. My brother in law was somewhat surprised, too, of how hard you had to step and pull mine to stop.

3 sets of new brake pads were installed – that only made it worse. Now the brakes stuck slightly to the two front discs. Ergo it had to be lack of movement in the calibres. 3 sets repair kits for the Brembos were bought. Immense difference. Now it was suddenly able to brake. Strangely enough I hadnt wondered why the brakes were weak – once again compared to my Nimbus. Its brakes might have been modern in the 30ties, but…….

Later stainless steel braided brake lines have been installed, improving things even more.

Another thing that bothered especially my wife, was the fact that the bike, after a drive, leaked a few drops of oil on the slabs. Some say that a Guzzi doesnt leak oil – it marks its territory. Great explanation in my opinion – but my wife was not amused. Something had to be done once again.

There were at least two problems. The hoses from the oil pump to the cylinder heads were the original ones – that is 25 year old Italian rubber hoses. They were all stiff, they sweated a little and they were replaced. By the way, one of the hollow banjo bolts that connect the hoses to the cylinder heads broke, so they were all replaced in the same operation.

The other place that leaked oil was the hose from the breather box, which leads to nature itself. The breather box has a couple of functions. One of them is to separate oil from the air whirling round when the two big pistons rush up and down. The oil must be fed back into the engine, and the surplus air is sent into the air through a hose. This hose ends up under the cylinder block in front of the left side of rear wheel. Brilliant place to dump oil! This was the point of origin.

The guy that sold my brother in law his bike told us that his had had the same problem, but that a cleaning of the flap valve in the breather box had solved the problem. Ok – it cannot be that difficult, so when enough time had passed and the leaking had begun to annoy me too, the breather box was uninstalled. And lo and behold – there was a spring mounted flap valve. As far as I can figure out, it seems to have the function to create a vacuum in the crank. It doesnt do the job very well. At least it didnt help cleaning the valve. Several methods were tried out – for instance pouring engine cleaner in the breather box – leaving it there for an hour or so and then cleaning it out with water and blow drying it with compressed air. To my big frustration oil kept leaking from that hose. A question placed on the Australian Guzzi Exchange page returned several suggestions. One was to change the breather box with another bigger model, which can contain more oil and thus has a better chance to return the oil to the engine, before it fills up and starts polluting Mother Nature. Others thought that this bigger model wasnt worth the money, and that other more radical methods were called for.

I believed – and still do – that my Guzzi should be able to keep its oil inside without any problems if others could – and preferably without any radical methods. So after having thought about it for a while I ordered a new Agostini breather box. After having mounted it – new hoses everywhere since all the others also were crumbling, too – it was time for a drive. Not a drop – fantastic. Problem solved – or so I thought.

After the next long drive it had messed up the whole backend of the bike. The left side of the rim, the brake disc, everything was coated in oil. If I were to say anything positive about this, it has to be that the bike at least doesnt rust when covered in oil. Something was very wrong and I hadnt a clue in the world. A few calls to a guy who knows a lot more about Guzzis than I do, turned up a suggestion that made sense. The new and bigger breather box doesnt have a flap valve like the original. In return he thought that I should check the ball valve by the hole at the cylinder block, where the hose for the breather is fitted. Everything off once again – and what do you know? There was no ball valve! None had ever been there while I had been the proud owner of the bike. Whether it was Luigi by the assembly line who originally forgot and went home for his siesta instead, or whether a previous owner decided to save 20 grams by throwing out the valve, I dont know. But off I went to Slangerup to visit De Voss, spend a few Danish kroner in return for a valve, mount it – and problem solved! The flap valve on the old breather box must have worked a bit. But not well enough to solve the problem on its own. I am convinced that the old breather box would have worked, had the ball valve been in place. But I was happy and so was my wife.

Later I have found out that the model with a flap valve in the oil separator wasnt supposed to have a ball valve. So: Im very sorry Luigi, for having suspected you. The grappa is on me next time.

At the valve cover it was prone to sweat a bit of oil, too. This, however, didnt seem to be so well known, but it turned out that the mating surface – especially the right one – wasnt completely straight. This was solved, by correcting it with a fine file.

Nice view.