Cylinder head - cleaning joint face

I agree with Chris and favour a mechanical method but prefer a scraper to the grinding paste as there wont be any metal removal when used carefully. Stanley do one incorporating a razor blade. Held at an acute angle to the surface it will cut through the gasket without marking the soft alloy.

You could also try cellulose thinner with some wire wool or similar, celly thinners softens most gasket goo's I've encountered over the years & is still reasonably easy to get hold of. If using a scraper, (the type Simon refers to are excellent for this) go easy on the head, the ally is quite soft & it's easy to damage, Chris's method avoids this risk & will ensure you have a nice flat mating surface.

As for the oil leak, a lot of heads are a little porous & can leak from between the push rod tunnels where the casting is thin, oil then runs down over the fins & gives the impression that it's coming from the head/barrel joint. I had/have this on my interstate & have added an extra breather to the inlet rocker cover & tee'd it into the original breather which has all but completely cured this. Also the two front studs that screw into the barrel can break through into the push rod tunnels & If the threads aren't sealed, the oil travels up the studs and looks just like a leaky head gasket, some silicon or similar on the threads usually works for this.

A quick google search for Norton Commando cylinder head oil leaks will give you some more possibilities & potential cures.

Best regards, Tim

I have found that bead blasting the head removes the old gaskets just fine. I always prefer solid copper gaskets to the composite ones, I have had minor oil leaks which never stopped me from getting home, but with the "Flame ring" composite ones, I have had blown head gaskets which did prevent me from getting home.

In America, I have come across a product called "Gasoila" which is an oil and petrol proof sealer. Painting the inside of castings with this prevents any porosity causing oil leaks.

I use one of those red coloured rotary disc scourers you can get at most Auto-jumbles. Those with a shank attached onlycost about £4 and will fit into a power drill chuck. They will clean off most rubbish in just seconds and leave the metal with a nice polished surface.

You don't need to apply any real pressure, just let the disc do the work. Do wear gloves, goggles and a mask as they can throw tiny fibres all over the place. Also be careful when using near sharp edges or corners as these will very quickly wear out the disc edge.

A good rinse of the parts will be needed afterwards, especially any areas where strayfibres might have landed.

Previously wrote:

I've just taken the head off my Mk 3 850 as oil appeared to be leaking from the head joint - I have checked all the usual suspect areas other than the head joint.

I suspect this might be the first time the head has come off since the bike left the factory.The problem is that the composite gasket has left a thin but very hard coating on the cylinder and barrel joint faces. I am struggling to properly clean up the faces. Does anybody have any good ideas for removing this. I've tried a scraper and soaking the remains of the gasket in petrol. It does not have much effect.

Thanks for advice.

Alan

I have used the plate glass method but with very fine wet and dry paper glued to the glass. Keep it wet and just work it and work it. This cured an oil leak from my head gasket. I should add that this was all done with the help of Ian Blayney, a Rolls Royce trained engineer. He will work for money and worth every penny. If you want to contact him for a quote on anything let me know. I could become his agent!!!

Andy