Drop engine in an afternoon., if you plus gas the nuts and bolts, need good trolly jack and 3 axle stands. 1 goes under the gearbox.
Engine complete onto a work bench, need engine hoist or 3 big people (with gloves)
Remove and clean tinware. ( a coat of hammerite would be nice.) 2 hrs.
Remove exhaust and heat exchangers (plus gas first) 2 hrs.
Remove cylinder head rhs, remove valves,( need correct tool, or home made) 2 hrs.
Clean and grind in valves. 2 hrs.
reassemble head 1 hr.
refit head and pushrod seals and valve gear. Set valve clearences, (need feeler gauge) 1 1/2 hrs.
repeat for lhs.
Build up motor with shiny tinware and hex head screws. afternoon.
refit motor (take your time, say 3 hrs.
Need gasket set, grinding paste, and a dob stick, the lot about £35.
Do a compression check first. Cold and hot.
Doing my clutch and crankcase oil seal this week end. I'll try and film it if I can.

Cordialement,