bike starts and runs nicely now thanks to advice from you chaps ironing out some little bits and bobs. It has just developed a bit of a leak where the exhaust pipe goes into the cylinder. I can both hear it and feel it and although the leak is not major I assume it might get worse so since there is no tightening ring which i was used to on non-British bikes that I rode before returning to motorcycling in my later years so how do i tighten up the join? There are no nuts and bolts on the outside at all so maybe it has to be done from the inside?
The pipe is just a push fit into the cylinder head - I gently tap it into place with a hide mallet. If the fit is sloppy you can try expanding the pipe a little, there are tools to do this but a shaped bit of wood hammered into the end can work well. Then you need to ensure that the other fittings for the pipe are secure and hold it in the head when they are tightened up. Finally, it is possible to use some sealant in the head (black bathroom silicone can work) to give a gas tight joint but don't overdo it.
The backfires resulting from a leaky joint can be annoying for anyone following you.