removing valve guides and top end

pete, I'm sure others will chime in but DO NOT use a centre punch or socket but DO use a soft brass or aluminium punch around 12mm dia or similar would be perfect,basically something of a softer material than the guide and a smaller diameter ideally so you can punch completely through the head if that makes sense.If it proves to be hard going getting initial movement you could warm the head up to expand the aluminium [in the oven or gently with a blowtorch]. I recently checked mine and found the wear to be on the valve stem and not the guide [ I just renewed the inlet valve ].

Its not easy to explain the valve lapping in procedure but I'm sure its got to be on youtube somewhere and not difficult once your used to the technique. You don't need any specialised kit,just a lapping stick with the rubber plungers on either end.

Take your pick on compression ratio's but I'm saying any increase puts extra load on the bottom end bearings but just my opinion.

Mate,

Dave Mitchell doing guides on old BSA. Renowned mechanic so should be helpful. Not a job I have tackled myself so good luck. Let us know how you get on.

Referring to increased compression ratio, minor 'improvement' in performance but all such changes mean that you increase the number of things that all need to be in perfect order before the bike will start easily and reliably. A bike in stock trim has a much broader and more forgiving range of conditions that allow for easy starting. That's certainly a factor in UK riding where long lay ups for winter are the norm.