gaskets on super suffolk punch 25A 75cc cast iron motor

It's normal practise with new gaskets to apply them dry unless the engine manufacturer specifically says otherwise.

As well as sealing, one of the functions of a gasket is to absorb minor irregularities between the mating surfaces. If it has lost its resilience and is compressed it will neither seal nor spread the load between the mating parts.

Ideally you would always renew gasket but on a fairly basic engine like your iron block Suffolk I wouldn't be too fussed about reusing gaskets that appear to be in good condition. Use a jointing compound if you wish but I often just use a smear of heavy grease on both sides of the gasket. In the case of the Iron block Suffolk I would, however renew the gasket between the block and the aluminium sump as the original gaskets seldom survive dismantling and usually end up paper thin and brittle. New sump gaskets are available from several sources, Jon Cruse at the Hailsham Mower Centre being one of them. 

Thanks for that, I will follow your advice.

I have seen head gaskets on ebay but I don't know if they are any good.

The original one looks ok and has a metallic appearance where as the ones on ebay look brown as if made from cardboard.

There appeared to be two paper gaskets together in the magneto plate for some reason I don't know if that was intentional or they were just stuck together when applied and appeared as one.

It's possible that the two gaskets were to achieve a small amount of crankshaft end float to allow for expansion as the engine reaches running temperature. Some manufacturers supply gaskets of different thicknesses in their gasket sets to achieve this but I've never seen a figure mentioned in any Suffolk literature.  On a cast iron block engine 2 to 5 thousandths of an inch should be ok but on a low stressed engine such as your Suffolk it will not be critical but some is necessary to prevent the crank binding up on warm up.

The original head gaskets were made out of a composition material , perhaps a reinforced cardboard!  The originals may have contained asbestos so the appearance of replacements will probably have changed. 

The end float is a tad excessive, the extra gasket may be causing this.

"In the case of the Iron block Suffolk I would, however renew the gasket between the block and the aluminium sump as the original gaskets seldom survive dismantling and usually end up paper thin and brittle"

- Would using Blue Hylomar instead of a new paper sump gasket work just as well?

I would say no as it won't give the cushioning effect of a gasket.

I will wait for a gasket then

Is it ordinary paper ? could I quickly scalpel one out of photo copy or epson print paper rather than have to what 5 days to get one?

I'd suggest that 80/90gm copy paper is too thin. Thin card would be better.

No "back street"  garage or motor bike shop in your area? Bound to have a sheet ot two of gasket paper for emergencies.

Can you remember how thick the last one you saw was? because, I maybe wrong, but I'm sure the stuff which peeled of the sump when I split from the body was paper thin , almost as thin as the magneto gasket, but I might be mistaken.

The valve chest gasket was very much thicker maybe card or cork

My stock gasket is 0.48 of a mm or 1/64th of an inch

off line for the rest of the evening!